diff --git a/AutoRest/Generators/CSharp/CSharp.Tests/AcceptanceTests.cs b/AutoRest/Generators/CSharp/CSharp.Tests/AcceptanceTests.cs
index 0d5c31f0e5182..9caea8d8df283 100644
--- a/AutoRest/Generators/CSharp/CSharp.Tests/AcceptanceTests.cs
+++ b/AutoRest/Generators/CSharp/CSharp.Tests/AcceptanceTests.cs
@@ -198,12 +198,16 @@ public void IntegerTests()
             client.IntModel.PutMin32(Int32.MinValue);
             client.IntModel.PutMax64(Int64.MaxValue);
             client.IntModel.PutMin64(Int64.MinValue);
+            client.IntModel.PutUnixTimeDate(new DateTime(2016, 4, 13, 0, 0, 0));
             client.IntModel.GetNull();
             Assert.Throws<SerializationException>(() => client.IntModel.GetInvalid());
             Assert.Throws<SerializationException>(() => client.IntModel.GetOverflowInt32());
             Assert.Throws<SerializationException>(() => client.IntModel.GetOverflowInt64());
             Assert.Throws<SerializationException>(() => client.IntModel.GetUnderflowInt32());
             Assert.Throws<SerializationException>(() => client.IntModel.GetUnderflowInt64());
+            Assert.Throws<SerializationException>(() => client.IntModel.GetInvalidUnixTime());
+            Assert.Null(client.IntModel.GetNullUnixTime());
+            Assert.Equal(new DateTime(2016, 4, 13, 0, 0, 0), client.IntModel.GetUnixTime());
         }
 
         [Fact]
diff --git a/AutoRest/Generators/CSharp/CSharp.Tests/Expected/AcceptanceTests/BodyInteger/IIntModel.cs b/AutoRest/Generators/CSharp/CSharp.Tests/Expected/AcceptanceTests/BodyInteger/IIntModel.cs
index 4b90323fef26b..7131504bb1855 100644
--- a/AutoRest/Generators/CSharp/CSharp.Tests/Expected/AcceptanceTests/BodyInteger/IIntModel.cs
+++ b/AutoRest/Generators/CSharp/CSharp.Tests/Expected/AcceptanceTests/BodyInteger/IIntModel.cs
@@ -129,5 +129,47 @@ public partial interface IIntModel
         /// The cancellation token.
         /// </param>
         Task<HttpOperationResponse> PutMin64WithHttpMessagesAsync(long intBody, Dictionary<string, List<string>> customHeaders = null, CancellationToken cancellationToken = default(CancellationToken));
+        /// <summary>
+        /// Get datetime encoded as Unix time value
+        /// </summary>
+        /// <param name='customHeaders'>
+        /// The headers that will be added to request.
+        /// </param>
+        /// <param name='cancellationToken'>
+        /// The cancellation token.
+        /// </param>
+        Task<HttpOperationResponse<DateTime?>> GetUnixTimeWithHttpMessagesAsync(Dictionary<string, List<string>> customHeaders = null, CancellationToken cancellationToken = default(CancellationToken));
+        /// <summary>
+        /// Put datetime encoded as Unix time
+        /// </summary>
+        /// <param name='intBody'>
+        /// </param>
+        /// <param name='customHeaders'>
+        /// The headers that will be added to request.
+        /// </param>
+        /// <param name='cancellationToken'>
+        /// The cancellation token.
+        /// </param>
+        Task<HttpOperationResponse> PutUnixTimeDateWithHttpMessagesAsync(DateTime intBody, Dictionary<string, List<string>> customHeaders = null, CancellationToken cancellationToken = default(CancellationToken));
+        /// <summary>
+        /// Get invalid Unix time value
+        /// </summary>
+        /// <param name='customHeaders'>
+        /// The headers that will be added to request.
+        /// </param>
+        /// <param name='cancellationToken'>
+        /// The cancellation token.
+        /// </param>
+        Task<HttpOperationResponse<DateTime?>> GetInvalidUnixTimeWithHttpMessagesAsync(Dictionary<string, List<string>> customHeaders = null, CancellationToken cancellationToken = default(CancellationToken));
+        /// <summary>
+        /// Get null Unix time value
+        /// </summary>
+        /// <param name='customHeaders'>
+        /// The headers that will be added to request.
+        /// </param>
+        /// <param name='cancellationToken'>
+        /// The cancellation token.
+        /// </param>
+        Task<HttpOperationResponse<DateTime?>> GetNullUnixTimeWithHttpMessagesAsync(Dictionary<string, List<string>> customHeaders = null, CancellationToken cancellationToken = default(CancellationToken));
     }
 }
diff --git a/AutoRest/Generators/CSharp/CSharp.Tests/Expected/AcceptanceTests/BodyInteger/IntModel.cs b/AutoRest/Generators/CSharp/CSharp.Tests/Expected/AcceptanceTests/BodyInteger/IntModel.cs
index feb0d3013f373..9c9b57ebbb2a4 100644
--- a/AutoRest/Generators/CSharp/CSharp.Tests/Expected/AcceptanceTests/BodyInteger/IntModel.cs
+++ b/AutoRest/Generators/CSharp/CSharp.Tests/Expected/AcceptanceTests/BodyInteger/IntModel.cs
@@ -1202,5 +1202,472 @@ public IntModel(AutoRestIntegerTestService client)
             return _result;
         }
 
+        /// <summary>
+        /// Get datetime encoded as Unix time value
+        /// </summary>
+        /// <param name='customHeaders'>
+        /// Headers that will be added to request.
+        /// </param>
+        /// <param name='cancellationToken'>
+        /// The cancellation token.
+        /// </param>
+        /// <return>
+        /// A response object containing the response body and response headers.
+        /// </return>
+        public async Task<HttpOperationResponse<DateTime?>> GetUnixTimeWithHttpMessagesAsync(Dictionary<string, List<string>> customHeaders = null, CancellationToken cancellationToken = default(CancellationToken))
+        {
+            // Tracing
+            bool _shouldTrace = ServiceClientTracing.IsEnabled;
+            string _invocationId = null;
+            if (_shouldTrace)
+            {
+                _invocationId = ServiceClientTracing.NextInvocationId.ToString();
+                Dictionary<string, object> tracingParameters = new Dictionary<string, object>();
+                tracingParameters.Add("cancellationToken", cancellationToken);
+                ServiceClientTracing.Enter(_invocationId, this, "GetUnixTime", tracingParameters);
+            }
+            // Construct URL
+            var _baseUrl = this.Client.BaseUri.AbsoluteUri;
+            var _url = new Uri(new Uri(_baseUrl + (_baseUrl.EndsWith("/") ? "" : "/")), "int/unixtime").ToString();
+            // Create HTTP transport objects
+            HttpRequestMessage _httpRequest = new HttpRequestMessage();
+            HttpResponseMessage _httpResponse = null;
+            _httpRequest.Method = new HttpMethod("GET");
+            _httpRequest.RequestUri = new Uri(_url);
+            // Set Headers
+            if (customHeaders != null)
+            {
+                foreach(var _header in customHeaders)
+                {
+                    if (_httpRequest.Headers.Contains(_header.Key))
+                    {
+                        _httpRequest.Headers.Remove(_header.Key);
+                    }
+                    _httpRequest.Headers.TryAddWithoutValidation(_header.Key, _header.Value);
+                }
+            }
+
+            // Serialize Request
+            string _requestContent = null;
+            // Send Request
+            if (_shouldTrace)
+            {
+                ServiceClientTracing.SendRequest(_invocationId, _httpRequest);
+            }
+            cancellationToken.ThrowIfCancellationRequested();
+            _httpResponse = await this.Client.HttpClient.SendAsync(_httpRequest, cancellationToken).ConfigureAwait(false);
+            if (_shouldTrace)
+            {
+                ServiceClientTracing.ReceiveResponse(_invocationId, _httpResponse);
+            }
+            HttpStatusCode _statusCode = _httpResponse.StatusCode;
+            cancellationToken.ThrowIfCancellationRequested();
+            string _responseContent = null;
+            if ((int)_statusCode != 200)
+            {
+                var ex = new ErrorException(string.Format("Operation returned an invalid status code '{0}'", _statusCode));
+                try
+                {
+                    _responseContent = await _httpResponse.Content.ReadAsStringAsync().ConfigureAwait(false);
+                    Error _errorBody = SafeJsonConvert.DeserializeObject<Error>(_responseContent, this.Client.DeserializationSettings);
+                    if (_errorBody != null)
+                    {
+                        ex.Body = _errorBody;
+                    }
+                }
+                catch (JsonException)
+                {
+                    // Ignore the exception
+                }
+                ex.Request = new HttpRequestMessageWrapper(_httpRequest, _requestContent);
+                ex.Response = new HttpResponseMessageWrapper(_httpResponse, _responseContent);
+                if (_shouldTrace)
+                {
+                    ServiceClientTracing.Error(_invocationId, ex);
+                }
+                _httpRequest.Dispose();
+                if (_httpResponse != null)
+                {
+                    _httpResponse.Dispose();
+                }
+                throw ex;
+            }
+            // Create Result
+            var _result = new HttpOperationResponse<DateTime?>();
+            _result.Request = _httpRequest;
+            _result.Response = _httpResponse;
+            // Deserialize Response
+            if ((int)_statusCode == 200)
+            {
+                _responseContent = await _httpResponse.Content.ReadAsStringAsync().ConfigureAwait(false);
+                try
+                {
+                    _result.Body = SafeJsonConvert.DeserializeObject<DateTime?>(_responseContent, new UnixTimeJsonConverter());
+                }
+                catch (JsonException ex)
+                {
+                    _httpRequest.Dispose();
+                    if (_httpResponse != null)
+                    {
+                        _httpResponse.Dispose();
+                    }
+                    throw new SerializationException("Unable to deserialize the response.", _responseContent, ex);
+                }
+            }
+            if (_shouldTrace)
+            {
+                ServiceClientTracing.Exit(_invocationId, _result);
+            }
+            return _result;
+        }
+
+        /// <summary>
+        /// Put datetime encoded as Unix time
+        /// </summary>
+        /// <param name='intBody'>
+        /// </param>
+        /// <param name='customHeaders'>
+        /// Headers that will be added to request.
+        /// </param>
+        /// <param name='cancellationToken'>
+        /// The cancellation token.
+        /// </param>
+        /// <return>
+        /// A response object containing the response body and response headers.
+        /// </return>
+        public async Task<HttpOperationResponse> PutUnixTimeDateWithHttpMessagesAsync(DateTime intBody, Dictionary<string, List<string>> customHeaders = null, CancellationToken cancellationToken = default(CancellationToken))
+        {
+            // Tracing
+            bool _shouldTrace = ServiceClientTracing.IsEnabled;
+            string _invocationId = null;
+            if (_shouldTrace)
+            {
+                _invocationId = ServiceClientTracing.NextInvocationId.ToString();
+                Dictionary<string, object> tracingParameters = new Dictionary<string, object>();
+                tracingParameters.Add("intBody", intBody);
+                tracingParameters.Add("cancellationToken", cancellationToken);
+                ServiceClientTracing.Enter(_invocationId, this, "PutUnixTimeDate", tracingParameters);
+            }
+            // Construct URL
+            var _baseUrl = this.Client.BaseUri.AbsoluteUri;
+            var _url = new Uri(new Uri(_baseUrl + (_baseUrl.EndsWith("/") ? "" : "/")), "int/unixtime").ToString();
+            // Create HTTP transport objects
+            HttpRequestMessage _httpRequest = new HttpRequestMessage();
+            HttpResponseMessage _httpResponse = null;
+            _httpRequest.Method = new HttpMethod("PUT");
+            _httpRequest.RequestUri = new Uri(_url);
+            // Set Headers
+            if (customHeaders != null)
+            {
+                foreach(var _header in customHeaders)
+                {
+                    if (_httpRequest.Headers.Contains(_header.Key))
+                    {
+                        _httpRequest.Headers.Remove(_header.Key);
+                    }
+                    _httpRequest.Headers.TryAddWithoutValidation(_header.Key, _header.Value);
+                }
+            }
+
+            // Serialize Request
+            string _requestContent = null;
+            if(intBody != null)
+            {
+                _requestContent = SafeJsonConvert.SerializeObject(intBody, new UnixTimeJsonConverter());
+                _httpRequest.Content = new StringContent(_requestContent, Encoding.UTF8);
+                _httpRequest.Content.Headers.ContentType = MediaTypeHeaderValue.Parse("application/json; charset=utf-8");
+            }
+            // Send Request
+            if (_shouldTrace)
+            {
+                ServiceClientTracing.SendRequest(_invocationId, _httpRequest);
+            }
+            cancellationToken.ThrowIfCancellationRequested();
+            _httpResponse = await this.Client.HttpClient.SendAsync(_httpRequest, cancellationToken).ConfigureAwait(false);
+            if (_shouldTrace)
+            {
+                ServiceClientTracing.ReceiveResponse(_invocationId, _httpResponse);
+            }
+            HttpStatusCode _statusCode = _httpResponse.StatusCode;
+            cancellationToken.ThrowIfCancellationRequested();
+            string _responseContent = null;
+            if ((int)_statusCode != 200)
+            {
+                var ex = new ErrorException(string.Format("Operation returned an invalid status code '{0}'", _statusCode));
+                try
+                {
+                    _responseContent = await _httpResponse.Content.ReadAsStringAsync().ConfigureAwait(false);
+                    Error _errorBody = SafeJsonConvert.DeserializeObject<Error>(_responseContent, this.Client.DeserializationSettings);
+                    if (_errorBody != null)
+                    {
+                        ex.Body = _errorBody;
+                    }
+                }
+                catch (JsonException)
+                {
+                    // Ignore the exception
+                }
+                ex.Request = new HttpRequestMessageWrapper(_httpRequest, _requestContent);
+                ex.Response = new HttpResponseMessageWrapper(_httpResponse, _responseContent);
+                if (_shouldTrace)
+                {
+                    ServiceClientTracing.Error(_invocationId, ex);
+                }
+                _httpRequest.Dispose();
+                if (_httpResponse != null)
+                {
+                    _httpResponse.Dispose();
+                }
+                throw ex;
+            }
+            // Create Result
+            var _result = new HttpOperationResponse();
+            _result.Request = _httpRequest;
+            _result.Response = _httpResponse;
+            if (_shouldTrace)
+            {
+                ServiceClientTracing.Exit(_invocationId, _result);
+            }
+            return _result;
+        }
+
+        /// <summary>
+        /// Get invalid Unix time value
+        /// </summary>
+        /// <param name='customHeaders'>
+        /// Headers that will be added to request.
+        /// </param>
+        /// <param name='cancellationToken'>
+        /// The cancellation token.
+        /// </param>
+        /// <return>
+        /// A response object containing the response body and response headers.
+        /// </return>
+        public async Task<HttpOperationResponse<DateTime?>> GetInvalidUnixTimeWithHttpMessagesAsync(Dictionary<string, List<string>> customHeaders = null, CancellationToken cancellationToken = default(CancellationToken))
+        {
+            // Tracing
+            bool _shouldTrace = ServiceClientTracing.IsEnabled;
+            string _invocationId = null;
+            if (_shouldTrace)
+            {
+                _invocationId = ServiceClientTracing.NextInvocationId.ToString();
+                Dictionary<string, object> tracingParameters = new Dictionary<string, object>();
+                tracingParameters.Add("cancellationToken", cancellationToken);
+                ServiceClientTracing.Enter(_invocationId, this, "GetInvalidUnixTime", tracingParameters);
+            }
+            // Construct URL
+            var _baseUrl = this.Client.BaseUri.AbsoluteUri;
+            var _url = new Uri(new Uri(_baseUrl + (_baseUrl.EndsWith("/") ? "" : "/")), "int/invalidunixtime").ToString();
+            // Create HTTP transport objects
+            HttpRequestMessage _httpRequest = new HttpRequestMessage();
+            HttpResponseMessage _httpResponse = null;
+            _httpRequest.Method = new HttpMethod("GET");
+            _httpRequest.RequestUri = new Uri(_url);
+            // Set Headers
+            if (customHeaders != null)
+            {
+                foreach(var _header in customHeaders)
+                {
+                    if (_httpRequest.Headers.Contains(_header.Key))
+                    {
+                        _httpRequest.Headers.Remove(_header.Key);
+                    }
+                    _httpRequest.Headers.TryAddWithoutValidation(_header.Key, _header.Value);
+                }
+            }
+
+            // Serialize Request
+            string _requestContent = null;
+            // Send Request
+            if (_shouldTrace)
+            {
+                ServiceClientTracing.SendRequest(_invocationId, _httpRequest);
+            }
+            cancellationToken.ThrowIfCancellationRequested();
+            _httpResponse = await this.Client.HttpClient.SendAsync(_httpRequest, cancellationToken).ConfigureAwait(false);
+            if (_shouldTrace)
+            {
+                ServiceClientTracing.ReceiveResponse(_invocationId, _httpResponse);
+            }
+            HttpStatusCode _statusCode = _httpResponse.StatusCode;
+            cancellationToken.ThrowIfCancellationRequested();
+            string _responseContent = null;
+            if ((int)_statusCode != 200)
+            {
+                var ex = new ErrorException(string.Format("Operation returned an invalid status code '{0}'", _statusCode));
+                try
+                {
+                    _responseContent = await _httpResponse.Content.ReadAsStringAsync().ConfigureAwait(false);
+                    Error _errorBody = SafeJsonConvert.DeserializeObject<Error>(_responseContent, this.Client.DeserializationSettings);
+                    if (_errorBody != null)
+                    {
+                        ex.Body = _errorBody;
+                    }
+                }
+                catch (JsonException)
+                {
+                    // Ignore the exception
+                }
+                ex.Request = new HttpRequestMessageWrapper(_httpRequest, _requestContent);
+                ex.Response = new HttpResponseMessageWrapper(_httpResponse, _responseContent);
+                if (_shouldTrace)
+                {
+                    ServiceClientTracing.Error(_invocationId, ex);
+                }
+                _httpRequest.Dispose();
+                if (_httpResponse != null)
+                {
+                    _httpResponse.Dispose();
+                }
+                throw ex;
+            }
+            // Create Result
+            var _result = new HttpOperationResponse<DateTime?>();
+            _result.Request = _httpRequest;
+            _result.Response = _httpResponse;
+            // Deserialize Response
+            if ((int)_statusCode == 200)
+            {
+                _responseContent = await _httpResponse.Content.ReadAsStringAsync().ConfigureAwait(false);
+                try
+                {
+                    _result.Body = SafeJsonConvert.DeserializeObject<DateTime?>(_responseContent, new UnixTimeJsonConverter());
+                }
+                catch (JsonException ex)
+                {
+                    _httpRequest.Dispose();
+                    if (_httpResponse != null)
+                    {
+                        _httpResponse.Dispose();
+                    }
+                    throw new SerializationException("Unable to deserialize the response.", _responseContent, ex);
+                }
+            }
+            if (_shouldTrace)
+            {
+                ServiceClientTracing.Exit(_invocationId, _result);
+            }
+            return _result;
+        }
+
+        /// <summary>
+        /// Get null Unix time value
+        /// </summary>
+        /// <param name='customHeaders'>
+        /// Headers that will be added to request.
+        /// </param>
+        /// <param name='cancellationToken'>
+        /// The cancellation token.
+        /// </param>
+        /// <return>
+        /// A response object containing the response body and response headers.
+        /// </return>
+        public async Task<HttpOperationResponse<DateTime?>> GetNullUnixTimeWithHttpMessagesAsync(Dictionary<string, List<string>> customHeaders = null, CancellationToken cancellationToken = default(CancellationToken))
+        {
+            // Tracing
+            bool _shouldTrace = ServiceClientTracing.IsEnabled;
+            string _invocationId = null;
+            if (_shouldTrace)
+            {
+                _invocationId = ServiceClientTracing.NextInvocationId.ToString();
+                Dictionary<string, object> tracingParameters = new Dictionary<string, object>();
+                tracingParameters.Add("cancellationToken", cancellationToken);
+                ServiceClientTracing.Enter(_invocationId, this, "GetNullUnixTime", tracingParameters);
+            }
+            // Construct URL
+            var _baseUrl = this.Client.BaseUri.AbsoluteUri;
+            var _url = new Uri(new Uri(_baseUrl + (_baseUrl.EndsWith("/") ? "" : "/")), "int/nullunixtime").ToString();
+            // Create HTTP transport objects
+            HttpRequestMessage _httpRequest = new HttpRequestMessage();
+            HttpResponseMessage _httpResponse = null;
+            _httpRequest.Method = new HttpMethod("GET");
+            _httpRequest.RequestUri = new Uri(_url);
+            // Set Headers
+            if (customHeaders != null)
+            {
+                foreach(var _header in customHeaders)
+                {
+                    if (_httpRequest.Headers.Contains(_header.Key))
+                    {
+                        _httpRequest.Headers.Remove(_header.Key);
+                    }
+                    _httpRequest.Headers.TryAddWithoutValidation(_header.Key, _header.Value);
+                }
+            }
+
+            // Serialize Request
+            string _requestContent = null;
+            // Send Request
+            if (_shouldTrace)
+            {
+                ServiceClientTracing.SendRequest(_invocationId, _httpRequest);
+            }
+            cancellationToken.ThrowIfCancellationRequested();
+            _httpResponse = await this.Client.HttpClient.SendAsync(_httpRequest, cancellationToken).ConfigureAwait(false);
+            if (_shouldTrace)
+            {
+                ServiceClientTracing.ReceiveResponse(_invocationId, _httpResponse);
+            }
+            HttpStatusCode _statusCode = _httpResponse.StatusCode;
+            cancellationToken.ThrowIfCancellationRequested();
+            string _responseContent = null;
+            if ((int)_statusCode != 200)
+            {
+                var ex = new ErrorException(string.Format("Operation returned an invalid status code '{0}'", _statusCode));
+                try
+                {
+                    _responseContent = await _httpResponse.Content.ReadAsStringAsync().ConfigureAwait(false);
+                    Error _errorBody = SafeJsonConvert.DeserializeObject<Error>(_responseContent, this.Client.DeserializationSettings);
+                    if (_errorBody != null)
+                    {
+                        ex.Body = _errorBody;
+                    }
+                }
+                catch (JsonException)
+                {
+                    // Ignore the exception
+                }
+                ex.Request = new HttpRequestMessageWrapper(_httpRequest, _requestContent);
+                ex.Response = new HttpResponseMessageWrapper(_httpResponse, _responseContent);
+                if (_shouldTrace)
+                {
+                    ServiceClientTracing.Error(_invocationId, ex);
+                }
+                _httpRequest.Dispose();
+                if (_httpResponse != null)
+                {
+                    _httpResponse.Dispose();
+                }
+                throw ex;
+            }
+            // Create Result
+            var _result = new HttpOperationResponse<DateTime?>();
+            _result.Request = _httpRequest;
+            _result.Response = _httpResponse;
+            // Deserialize Response
+            if ((int)_statusCode == 200)
+            {
+                _responseContent = await _httpResponse.Content.ReadAsStringAsync().ConfigureAwait(false);
+                try
+                {
+                    _result.Body = SafeJsonConvert.DeserializeObject<DateTime?>(_responseContent, new UnixTimeJsonConverter());
+                }
+                catch (JsonException ex)
+                {
+                    _httpRequest.Dispose();
+                    if (_httpResponse != null)
+                    {
+                        _httpResponse.Dispose();
+                    }
+                    throw new SerializationException("Unable to deserialize the response.", _responseContent, ex);
+                }
+            }
+            if (_shouldTrace)
+            {
+                ServiceClientTracing.Exit(_invocationId, _result);
+            }
+            return _result;
+        }
+
     }
 }
diff --git a/AutoRest/Generators/CSharp/CSharp.Tests/Expected/AcceptanceTests/BodyInteger/IntModelExtensions.cs b/AutoRest/Generators/CSharp/CSharp.Tests/Expected/AcceptanceTests/BodyInteger/IntModelExtensions.cs
index 0c57e20b0aade..c0bc0812ebde8 100644
--- a/AutoRest/Generators/CSharp/CSharp.Tests/Expected/AcceptanceTests/BodyInteger/IntModelExtensions.cs
+++ b/AutoRest/Generators/CSharp/CSharp.Tests/Expected/AcceptanceTests/BodyInteger/IntModelExtensions.cs
@@ -305,5 +305,118 @@ public static void PutMin64(this IIntModel operations, long intBody)
                 await operations.PutMin64WithHttpMessagesAsync(intBody, null, cancellationToken).ConfigureAwait(false);
             }
 
+            /// <summary>
+            /// Get datetime encoded as Unix time value
+            /// </summary>
+            /// <param name='operations'>
+            /// The operations group for this extension method.
+            /// </param>
+            public static DateTime? GetUnixTime(this IIntModel operations)
+            {
+                return Task.Factory.StartNew(s => ((IIntModel)s).GetUnixTimeAsync(), operations, CancellationToken.None, TaskCreationOptions.None, TaskScheduler.Default).Unwrap().GetAwaiter().GetResult();
+            }
+
+            /// <summary>
+            /// Get datetime encoded as Unix time value
+            /// </summary>
+            /// <param name='operations'>
+            /// The operations group for this extension method.
+            /// </param>
+            /// <param name='cancellationToken'>
+            /// The cancellation token.
+            /// </param>
+            public static async Task<DateTime?> GetUnixTimeAsync(this IIntModel operations, CancellationToken cancellationToken = default(CancellationToken))
+            {
+                using (var _result = await operations.GetUnixTimeWithHttpMessagesAsync(null, cancellationToken).ConfigureAwait(false))
+                {
+                    return _result.Body;
+                }
+            }
+
+            /// <summary>
+            /// Put datetime encoded as Unix time
+            /// </summary>
+            /// <param name='operations'>
+            /// The operations group for this extension method.
+            /// </param>
+            /// <param name='intBody'>
+            /// </param>
+            public static void PutUnixTimeDate(this IIntModel operations, DateTime intBody)
+            {
+                Task.Factory.StartNew(s => ((IIntModel)s).PutUnixTimeDateAsync(intBody), operations, CancellationToken.None, TaskCreationOptions.None, TaskScheduler.Default).Unwrap().GetAwaiter().GetResult();
+            }
+
+            /// <summary>
+            /// Put datetime encoded as Unix time
+            /// </summary>
+            /// <param name='operations'>
+            /// The operations group for this extension method.
+            /// </param>
+            /// <param name='intBody'>
+            /// </param>
+            /// <param name='cancellationToken'>
+            /// The cancellation token.
+            /// </param>
+            public static async Task PutUnixTimeDateAsync(this IIntModel operations, DateTime intBody, CancellationToken cancellationToken = default(CancellationToken))
+            {
+                await operations.PutUnixTimeDateWithHttpMessagesAsync(intBody, null, cancellationToken).ConfigureAwait(false);
+            }
+
+            /// <summary>
+            /// Get invalid Unix time value
+            /// </summary>
+            /// <param name='operations'>
+            /// The operations group for this extension method.
+            /// </param>
+            public static DateTime? GetInvalidUnixTime(this IIntModel operations)
+            {
+                return Task.Factory.StartNew(s => ((IIntModel)s).GetInvalidUnixTimeAsync(), operations, CancellationToken.None, TaskCreationOptions.None, TaskScheduler.Default).Unwrap().GetAwaiter().GetResult();
+            }
+
+            /// <summary>
+            /// Get invalid Unix time value
+            /// </summary>
+            /// <param name='operations'>
+            /// The operations group for this extension method.
+            /// </param>
+            /// <param name='cancellationToken'>
+            /// The cancellation token.
+            /// </param>
+            public static async Task<DateTime?> GetInvalidUnixTimeAsync(this IIntModel operations, CancellationToken cancellationToken = default(CancellationToken))
+            {
+                using (var _result = await operations.GetInvalidUnixTimeWithHttpMessagesAsync(null, cancellationToken).ConfigureAwait(false))
+                {
+                    return _result.Body;
+                }
+            }
+
+            /// <summary>
+            /// Get null Unix time value
+            /// </summary>
+            /// <param name='operations'>
+            /// The operations group for this extension method.
+            /// </param>
+            public static DateTime? GetNullUnixTime(this IIntModel operations)
+            {
+                return Task.Factory.StartNew(s => ((IIntModel)s).GetNullUnixTimeAsync(), operations, CancellationToken.None, TaskCreationOptions.None, TaskScheduler.Default).Unwrap().GetAwaiter().GetResult();
+            }
+
+            /// <summary>
+            /// Get null Unix time value
+            /// </summary>
+            /// <param name='operations'>
+            /// The operations group for this extension method.
+            /// </param>
+            /// <param name='cancellationToken'>
+            /// The cancellation token.
+            /// </param>
+            public static async Task<DateTime?> GetNullUnixTimeAsync(this IIntModel operations, CancellationToken cancellationToken = default(CancellationToken))
+            {
+                using (var _result = await operations.GetNullUnixTimeWithHttpMessagesAsync(null, cancellationToken).ConfigureAwait(false))
+                {
+                    return _result.Body;
+                }
+            }
+
     }
 }
diff --git a/AutoRest/Generators/CSharp/CSharp.Tests/Expected/AcceptanceTests/CompositeBoolIntClient/IIntModel.cs b/AutoRest/Generators/CSharp/CSharp.Tests/Expected/AcceptanceTests/CompositeBoolIntClient/IIntModel.cs
index 4917e355224d7..d0b518478669c 100644
--- a/AutoRest/Generators/CSharp/CSharp.Tests/Expected/AcceptanceTests/CompositeBoolIntClient/IIntModel.cs
+++ b/AutoRest/Generators/CSharp/CSharp.Tests/Expected/AcceptanceTests/CompositeBoolIntClient/IIntModel.cs
@@ -129,5 +129,47 @@ public partial interface IIntModel
         /// The cancellation token.
         /// </param>
         Task<HttpOperationResponse> PutMin64WithHttpMessagesAsync(long intBody, Dictionary<string, List<string>> customHeaders = null, CancellationToken cancellationToken = default(CancellationToken));
+        /// <summary>
+        /// Get datetime encoded as Unix time value
+        /// </summary>
+        /// <param name='customHeaders'>
+        /// The headers that will be added to request.
+        /// </param>
+        /// <param name='cancellationToken'>
+        /// The cancellation token.
+        /// </param>
+        Task<HttpOperationResponse<DateTime?>> GetUnixTimeWithHttpMessagesAsync(Dictionary<string, List<string>> customHeaders = null, CancellationToken cancellationToken = default(CancellationToken));
+        /// <summary>
+        /// Put datetime encoded as Unix time
+        /// </summary>
+        /// <param name='intBody'>
+        /// </param>
+        /// <param name='customHeaders'>
+        /// The headers that will be added to request.
+        /// </param>
+        /// <param name='cancellationToken'>
+        /// The cancellation token.
+        /// </param>
+        Task<HttpOperationResponse> PutUnixTimeDateWithHttpMessagesAsync(DateTime intBody, Dictionary<string, List<string>> customHeaders = null, CancellationToken cancellationToken = default(CancellationToken));
+        /// <summary>
+        /// Get invalid Unix time value
+        /// </summary>
+        /// <param name='customHeaders'>
+        /// The headers that will be added to request.
+        /// </param>
+        /// <param name='cancellationToken'>
+        /// The cancellation token.
+        /// </param>
+        Task<HttpOperationResponse<DateTime?>> GetInvalidUnixTimeWithHttpMessagesAsync(Dictionary<string, List<string>> customHeaders = null, CancellationToken cancellationToken = default(CancellationToken));
+        /// <summary>
+        /// Get null Unix time value
+        /// </summary>
+        /// <param name='customHeaders'>
+        /// The headers that will be added to request.
+        /// </param>
+        /// <param name='cancellationToken'>
+        /// The cancellation token.
+        /// </param>
+        Task<HttpOperationResponse<DateTime?>> GetNullUnixTimeWithHttpMessagesAsync(Dictionary<string, List<string>> customHeaders = null, CancellationToken cancellationToken = default(CancellationToken));
     }
 }
diff --git a/AutoRest/Generators/CSharp/CSharp.Tests/Expected/AcceptanceTests/CompositeBoolIntClient/IntModel.cs b/AutoRest/Generators/CSharp/CSharp.Tests/Expected/AcceptanceTests/CompositeBoolIntClient/IntModel.cs
index 1ed42f86ca54e..2047fd860871e 100644
--- a/AutoRest/Generators/CSharp/CSharp.Tests/Expected/AcceptanceTests/CompositeBoolIntClient/IntModel.cs
+++ b/AutoRest/Generators/CSharp/CSharp.Tests/Expected/AcceptanceTests/CompositeBoolIntClient/IntModel.cs
@@ -1202,5 +1202,472 @@ public IntModel(CompositeBoolInt client)
             return _result;
         }
 
+        /// <summary>
+        /// Get datetime encoded as Unix time value
+        /// </summary>
+        /// <param name='customHeaders'>
+        /// Headers that will be added to request.
+        /// </param>
+        /// <param name='cancellationToken'>
+        /// The cancellation token.
+        /// </param>
+        /// <return>
+        /// A response object containing the response body and response headers.
+        /// </return>
+        public async Task<HttpOperationResponse<DateTime?>> GetUnixTimeWithHttpMessagesAsync(Dictionary<string, List<string>> customHeaders = null, CancellationToken cancellationToken = default(CancellationToken))
+        {
+            // Tracing
+            bool _shouldTrace = ServiceClientTracing.IsEnabled;
+            string _invocationId = null;
+            if (_shouldTrace)
+            {
+                _invocationId = ServiceClientTracing.NextInvocationId.ToString();
+                Dictionary<string, object> tracingParameters = new Dictionary<string, object>();
+                tracingParameters.Add("cancellationToken", cancellationToken);
+                ServiceClientTracing.Enter(_invocationId, this, "GetUnixTime", tracingParameters);
+            }
+            // Construct URL
+            var _baseUrl = this.Client.BaseUri.AbsoluteUri;
+            var _url = new Uri(new Uri(_baseUrl + (_baseUrl.EndsWith("/") ? "" : "/")), "int/unixtime").ToString();
+            // Create HTTP transport objects
+            HttpRequestMessage _httpRequest = new HttpRequestMessage();
+            HttpResponseMessage _httpResponse = null;
+            _httpRequest.Method = new HttpMethod("GET");
+            _httpRequest.RequestUri = new Uri(_url);
+            // Set Headers
+            if (customHeaders != null)
+            {
+                foreach(var _header in customHeaders)
+                {
+                    if (_httpRequest.Headers.Contains(_header.Key))
+                    {
+                        _httpRequest.Headers.Remove(_header.Key);
+                    }
+                    _httpRequest.Headers.TryAddWithoutValidation(_header.Key, _header.Value);
+                }
+            }
+
+            // Serialize Request
+            string _requestContent = null;
+            // Send Request
+            if (_shouldTrace)
+            {
+                ServiceClientTracing.SendRequest(_invocationId, _httpRequest);
+            }
+            cancellationToken.ThrowIfCancellationRequested();
+            _httpResponse = await this.Client.HttpClient.SendAsync(_httpRequest, cancellationToken).ConfigureAwait(false);
+            if (_shouldTrace)
+            {
+                ServiceClientTracing.ReceiveResponse(_invocationId, _httpResponse);
+            }
+            HttpStatusCode _statusCode = _httpResponse.StatusCode;
+            cancellationToken.ThrowIfCancellationRequested();
+            string _responseContent = null;
+            if ((int)_statusCode != 200)
+            {
+                var ex = new ErrorException(string.Format("Operation returned an invalid status code '{0}'", _statusCode));
+                try
+                {
+                    _responseContent = await _httpResponse.Content.ReadAsStringAsync().ConfigureAwait(false);
+                    Error _errorBody = SafeJsonConvert.DeserializeObject<Error>(_responseContent, this.Client.DeserializationSettings);
+                    if (_errorBody != null)
+                    {
+                        ex.Body = _errorBody;
+                    }
+                }
+                catch (JsonException)
+                {
+                    // Ignore the exception
+                }
+                ex.Request = new HttpRequestMessageWrapper(_httpRequest, _requestContent);
+                ex.Response = new HttpResponseMessageWrapper(_httpResponse, _responseContent);
+                if (_shouldTrace)
+                {
+                    ServiceClientTracing.Error(_invocationId, ex);
+                }
+                _httpRequest.Dispose();
+                if (_httpResponse != null)
+                {
+                    _httpResponse.Dispose();
+                }
+                throw ex;
+            }
+            // Create Result
+            var _result = new HttpOperationResponse<DateTime?>();
+            _result.Request = _httpRequest;
+            _result.Response = _httpResponse;
+            // Deserialize Response
+            if ((int)_statusCode == 200)
+            {
+                _responseContent = await _httpResponse.Content.ReadAsStringAsync().ConfigureAwait(false);
+                try
+                {
+                    _result.Body = SafeJsonConvert.DeserializeObject<DateTime?>(_responseContent, new UnixTimeJsonConverter());
+                }
+                catch (JsonException ex)
+                {
+                    _httpRequest.Dispose();
+                    if (_httpResponse != null)
+                    {
+                        _httpResponse.Dispose();
+                    }
+                    throw new SerializationException("Unable to deserialize the response.", _responseContent, ex);
+                }
+            }
+            if (_shouldTrace)
+            {
+                ServiceClientTracing.Exit(_invocationId, _result);
+            }
+            return _result;
+        }
+
+        /// <summary>
+        /// Put datetime encoded as Unix time
+        /// </summary>
+        /// <param name='intBody'>
+        /// </param>
+        /// <param name='customHeaders'>
+        /// Headers that will be added to request.
+        /// </param>
+        /// <param name='cancellationToken'>
+        /// The cancellation token.
+        /// </param>
+        /// <return>
+        /// A response object containing the response body and response headers.
+        /// </return>
+        public async Task<HttpOperationResponse> PutUnixTimeDateWithHttpMessagesAsync(DateTime intBody, Dictionary<string, List<string>> customHeaders = null, CancellationToken cancellationToken = default(CancellationToken))
+        {
+            // Tracing
+            bool _shouldTrace = ServiceClientTracing.IsEnabled;
+            string _invocationId = null;
+            if (_shouldTrace)
+            {
+                _invocationId = ServiceClientTracing.NextInvocationId.ToString();
+                Dictionary<string, object> tracingParameters = new Dictionary<string, object>();
+                tracingParameters.Add("intBody", intBody);
+                tracingParameters.Add("cancellationToken", cancellationToken);
+                ServiceClientTracing.Enter(_invocationId, this, "PutUnixTimeDate", tracingParameters);
+            }
+            // Construct URL
+            var _baseUrl = this.Client.BaseUri.AbsoluteUri;
+            var _url = new Uri(new Uri(_baseUrl + (_baseUrl.EndsWith("/") ? "" : "/")), "int/unixtime").ToString();
+            // Create HTTP transport objects
+            HttpRequestMessage _httpRequest = new HttpRequestMessage();
+            HttpResponseMessage _httpResponse = null;
+            _httpRequest.Method = new HttpMethod("PUT");
+            _httpRequest.RequestUri = new Uri(_url);
+            // Set Headers
+            if (customHeaders != null)
+            {
+                foreach(var _header in customHeaders)
+                {
+                    if (_httpRequest.Headers.Contains(_header.Key))
+                    {
+                        _httpRequest.Headers.Remove(_header.Key);
+                    }
+                    _httpRequest.Headers.TryAddWithoutValidation(_header.Key, _header.Value);
+                }
+            }
+
+            // Serialize Request
+            string _requestContent = null;
+            if(intBody != null)
+            {
+                _requestContent = SafeJsonConvert.SerializeObject(intBody, new UnixTimeJsonConverter());
+                _httpRequest.Content = new StringContent(_requestContent, Encoding.UTF8);
+                _httpRequest.Content.Headers.ContentType = MediaTypeHeaderValue.Parse("application/json; charset=utf-8");
+            }
+            // Send Request
+            if (_shouldTrace)
+            {
+                ServiceClientTracing.SendRequest(_invocationId, _httpRequest);
+            }
+            cancellationToken.ThrowIfCancellationRequested();
+            _httpResponse = await this.Client.HttpClient.SendAsync(_httpRequest, cancellationToken).ConfigureAwait(false);
+            if (_shouldTrace)
+            {
+                ServiceClientTracing.ReceiveResponse(_invocationId, _httpResponse);
+            }
+            HttpStatusCode _statusCode = _httpResponse.StatusCode;
+            cancellationToken.ThrowIfCancellationRequested();
+            string _responseContent = null;
+            if ((int)_statusCode != 200)
+            {
+                var ex = new ErrorException(string.Format("Operation returned an invalid status code '{0}'", _statusCode));
+                try
+                {
+                    _responseContent = await _httpResponse.Content.ReadAsStringAsync().ConfigureAwait(false);
+                    Error _errorBody = SafeJsonConvert.DeserializeObject<Error>(_responseContent, this.Client.DeserializationSettings);
+                    if (_errorBody != null)
+                    {
+                        ex.Body = _errorBody;
+                    }
+                }
+                catch (JsonException)
+                {
+                    // Ignore the exception
+                }
+                ex.Request = new HttpRequestMessageWrapper(_httpRequest, _requestContent);
+                ex.Response = new HttpResponseMessageWrapper(_httpResponse, _responseContent);
+                if (_shouldTrace)
+                {
+                    ServiceClientTracing.Error(_invocationId, ex);
+                }
+                _httpRequest.Dispose();
+                if (_httpResponse != null)
+                {
+                    _httpResponse.Dispose();
+                }
+                throw ex;
+            }
+            // Create Result
+            var _result = new HttpOperationResponse();
+            _result.Request = _httpRequest;
+            _result.Response = _httpResponse;
+            if (_shouldTrace)
+            {
+                ServiceClientTracing.Exit(_invocationId, _result);
+            }
+            return _result;
+        }
+
+        /// <summary>
+        /// Get invalid Unix time value
+        /// </summary>
+        /// <param name='customHeaders'>
+        /// Headers that will be added to request.
+        /// </param>
+        /// <param name='cancellationToken'>
+        /// The cancellation token.
+        /// </param>
+        /// <return>
+        /// A response object containing the response body and response headers.
+        /// </return>
+        public async Task<HttpOperationResponse<DateTime?>> GetInvalidUnixTimeWithHttpMessagesAsync(Dictionary<string, List<string>> customHeaders = null, CancellationToken cancellationToken = default(CancellationToken))
+        {
+            // Tracing
+            bool _shouldTrace = ServiceClientTracing.IsEnabled;
+            string _invocationId = null;
+            if (_shouldTrace)
+            {
+                _invocationId = ServiceClientTracing.NextInvocationId.ToString();
+                Dictionary<string, object> tracingParameters = new Dictionary<string, object>();
+                tracingParameters.Add("cancellationToken", cancellationToken);
+                ServiceClientTracing.Enter(_invocationId, this, "GetInvalidUnixTime", tracingParameters);
+            }
+            // Construct URL
+            var _baseUrl = this.Client.BaseUri.AbsoluteUri;
+            var _url = new Uri(new Uri(_baseUrl + (_baseUrl.EndsWith("/") ? "" : "/")), "int/invalidunixtime").ToString();
+            // Create HTTP transport objects
+            HttpRequestMessage _httpRequest = new HttpRequestMessage();
+            HttpResponseMessage _httpResponse = null;
+            _httpRequest.Method = new HttpMethod("GET");
+            _httpRequest.RequestUri = new Uri(_url);
+            // Set Headers
+            if (customHeaders != null)
+            {
+                foreach(var _header in customHeaders)
+                {
+                    if (_httpRequest.Headers.Contains(_header.Key))
+                    {
+                        _httpRequest.Headers.Remove(_header.Key);
+                    }
+                    _httpRequest.Headers.TryAddWithoutValidation(_header.Key, _header.Value);
+                }
+            }
+
+            // Serialize Request
+            string _requestContent = null;
+            // Send Request
+            if (_shouldTrace)
+            {
+                ServiceClientTracing.SendRequest(_invocationId, _httpRequest);
+            }
+            cancellationToken.ThrowIfCancellationRequested();
+            _httpResponse = await this.Client.HttpClient.SendAsync(_httpRequest, cancellationToken).ConfigureAwait(false);
+            if (_shouldTrace)
+            {
+                ServiceClientTracing.ReceiveResponse(_invocationId, _httpResponse);
+            }
+            HttpStatusCode _statusCode = _httpResponse.StatusCode;
+            cancellationToken.ThrowIfCancellationRequested();
+            string _responseContent = null;
+            if ((int)_statusCode != 200)
+            {
+                var ex = new ErrorException(string.Format("Operation returned an invalid status code '{0}'", _statusCode));
+                try
+                {
+                    _responseContent = await _httpResponse.Content.ReadAsStringAsync().ConfigureAwait(false);
+                    Error _errorBody = SafeJsonConvert.DeserializeObject<Error>(_responseContent, this.Client.DeserializationSettings);
+                    if (_errorBody != null)
+                    {
+                        ex.Body = _errorBody;
+                    }
+                }
+                catch (JsonException)
+                {
+                    // Ignore the exception
+                }
+                ex.Request = new HttpRequestMessageWrapper(_httpRequest, _requestContent);
+                ex.Response = new HttpResponseMessageWrapper(_httpResponse, _responseContent);
+                if (_shouldTrace)
+                {
+                    ServiceClientTracing.Error(_invocationId, ex);
+                }
+                _httpRequest.Dispose();
+                if (_httpResponse != null)
+                {
+                    _httpResponse.Dispose();
+                }
+                throw ex;
+            }
+            // Create Result
+            var _result = new HttpOperationResponse<DateTime?>();
+            _result.Request = _httpRequest;
+            _result.Response = _httpResponse;
+            // Deserialize Response
+            if ((int)_statusCode == 200)
+            {
+                _responseContent = await _httpResponse.Content.ReadAsStringAsync().ConfigureAwait(false);
+                try
+                {
+                    _result.Body = SafeJsonConvert.DeserializeObject<DateTime?>(_responseContent, new UnixTimeJsonConverter());
+                }
+                catch (JsonException ex)
+                {
+                    _httpRequest.Dispose();
+                    if (_httpResponse != null)
+                    {
+                        _httpResponse.Dispose();
+                    }
+                    throw new SerializationException("Unable to deserialize the response.", _responseContent, ex);
+                }
+            }
+            if (_shouldTrace)
+            {
+                ServiceClientTracing.Exit(_invocationId, _result);
+            }
+            return _result;
+        }
+
+        /// <summary>
+        /// Get null Unix time value
+        /// </summary>
+        /// <param name='customHeaders'>
+        /// Headers that will be added to request.
+        /// </param>
+        /// <param name='cancellationToken'>
+        /// The cancellation token.
+        /// </param>
+        /// <return>
+        /// A response object containing the response body and response headers.
+        /// </return>
+        public async Task<HttpOperationResponse<DateTime?>> GetNullUnixTimeWithHttpMessagesAsync(Dictionary<string, List<string>> customHeaders = null, CancellationToken cancellationToken = default(CancellationToken))
+        {
+            // Tracing
+            bool _shouldTrace = ServiceClientTracing.IsEnabled;
+            string _invocationId = null;
+            if (_shouldTrace)
+            {
+                _invocationId = ServiceClientTracing.NextInvocationId.ToString();
+                Dictionary<string, object> tracingParameters = new Dictionary<string, object>();
+                tracingParameters.Add("cancellationToken", cancellationToken);
+                ServiceClientTracing.Enter(_invocationId, this, "GetNullUnixTime", tracingParameters);
+            }
+            // Construct URL
+            var _baseUrl = this.Client.BaseUri.AbsoluteUri;
+            var _url = new Uri(new Uri(_baseUrl + (_baseUrl.EndsWith("/") ? "" : "/")), "int/nullunixtime").ToString();
+            // Create HTTP transport objects
+            HttpRequestMessage _httpRequest = new HttpRequestMessage();
+            HttpResponseMessage _httpResponse = null;
+            _httpRequest.Method = new HttpMethod("GET");
+            _httpRequest.RequestUri = new Uri(_url);
+            // Set Headers
+            if (customHeaders != null)
+            {
+                foreach(var _header in customHeaders)
+                {
+                    if (_httpRequest.Headers.Contains(_header.Key))
+                    {
+                        _httpRequest.Headers.Remove(_header.Key);
+                    }
+                    _httpRequest.Headers.TryAddWithoutValidation(_header.Key, _header.Value);
+                }
+            }
+
+            // Serialize Request
+            string _requestContent = null;
+            // Send Request
+            if (_shouldTrace)
+            {
+                ServiceClientTracing.SendRequest(_invocationId, _httpRequest);
+            }
+            cancellationToken.ThrowIfCancellationRequested();
+            _httpResponse = await this.Client.HttpClient.SendAsync(_httpRequest, cancellationToken).ConfigureAwait(false);
+            if (_shouldTrace)
+            {
+                ServiceClientTracing.ReceiveResponse(_invocationId, _httpResponse);
+            }
+            HttpStatusCode _statusCode = _httpResponse.StatusCode;
+            cancellationToken.ThrowIfCancellationRequested();
+            string _responseContent = null;
+            if ((int)_statusCode != 200)
+            {
+                var ex = new ErrorException(string.Format("Operation returned an invalid status code '{0}'", _statusCode));
+                try
+                {
+                    _responseContent = await _httpResponse.Content.ReadAsStringAsync().ConfigureAwait(false);
+                    Error _errorBody = SafeJsonConvert.DeserializeObject<Error>(_responseContent, this.Client.DeserializationSettings);
+                    if (_errorBody != null)
+                    {
+                        ex.Body = _errorBody;
+                    }
+                }
+                catch (JsonException)
+                {
+                    // Ignore the exception
+                }
+                ex.Request = new HttpRequestMessageWrapper(_httpRequest, _requestContent);
+                ex.Response = new HttpResponseMessageWrapper(_httpResponse, _responseContent);
+                if (_shouldTrace)
+                {
+                    ServiceClientTracing.Error(_invocationId, ex);
+                }
+                _httpRequest.Dispose();
+                if (_httpResponse != null)
+                {
+                    _httpResponse.Dispose();
+                }
+                throw ex;
+            }
+            // Create Result
+            var _result = new HttpOperationResponse<DateTime?>();
+            _result.Request = _httpRequest;
+            _result.Response = _httpResponse;
+            // Deserialize Response
+            if ((int)_statusCode == 200)
+            {
+                _responseContent = await _httpResponse.Content.ReadAsStringAsync().ConfigureAwait(false);
+                try
+                {
+                    _result.Body = SafeJsonConvert.DeserializeObject<DateTime?>(_responseContent, new UnixTimeJsonConverter());
+                }
+                catch (JsonException ex)
+                {
+                    _httpRequest.Dispose();
+                    if (_httpResponse != null)
+                    {
+                        _httpResponse.Dispose();
+                    }
+                    throw new SerializationException("Unable to deserialize the response.", _responseContent, ex);
+                }
+            }
+            if (_shouldTrace)
+            {
+                ServiceClientTracing.Exit(_invocationId, _result);
+            }
+            return _result;
+        }
+
     }
 }
diff --git a/AutoRest/Generators/CSharp/CSharp.Tests/Expected/AcceptanceTests/CompositeBoolIntClient/IntModelExtensions.cs b/AutoRest/Generators/CSharp/CSharp.Tests/Expected/AcceptanceTests/CompositeBoolIntClient/IntModelExtensions.cs
index a203d3cee39e7..009277ea5077b 100644
--- a/AutoRest/Generators/CSharp/CSharp.Tests/Expected/AcceptanceTests/CompositeBoolIntClient/IntModelExtensions.cs
+++ b/AutoRest/Generators/CSharp/CSharp.Tests/Expected/AcceptanceTests/CompositeBoolIntClient/IntModelExtensions.cs
@@ -305,5 +305,118 @@ public static void PutMin64(this IIntModel operations, long intBody)
                 await operations.PutMin64WithHttpMessagesAsync(intBody, null, cancellationToken).ConfigureAwait(false);
             }
 
+            /// <summary>
+            /// Get datetime encoded as Unix time value
+            /// </summary>
+            /// <param name='operations'>
+            /// The operations group for this extension method.
+            /// </param>
+            public static DateTime? GetUnixTime(this IIntModel operations)
+            {
+                return Task.Factory.StartNew(s => ((IIntModel)s).GetUnixTimeAsync(), operations, CancellationToken.None, TaskCreationOptions.None, TaskScheduler.Default).Unwrap().GetAwaiter().GetResult();
+            }
+
+            /// <summary>
+            /// Get datetime encoded as Unix time value
+            /// </summary>
+            /// <param name='operations'>
+            /// The operations group for this extension method.
+            /// </param>
+            /// <param name='cancellationToken'>
+            /// The cancellation token.
+            /// </param>
+            public static async Task<DateTime?> GetUnixTimeAsync(this IIntModel operations, CancellationToken cancellationToken = default(CancellationToken))
+            {
+                using (var _result = await operations.GetUnixTimeWithHttpMessagesAsync(null, cancellationToken).ConfigureAwait(false))
+                {
+                    return _result.Body;
+                }
+            }
+
+            /// <summary>
+            /// Put datetime encoded as Unix time
+            /// </summary>
+            /// <param name='operations'>
+            /// The operations group for this extension method.
+            /// </param>
+            /// <param name='intBody'>
+            /// </param>
+            public static void PutUnixTimeDate(this IIntModel operations, DateTime intBody)
+            {
+                Task.Factory.StartNew(s => ((IIntModel)s).PutUnixTimeDateAsync(intBody), operations, CancellationToken.None, TaskCreationOptions.None, TaskScheduler.Default).Unwrap().GetAwaiter().GetResult();
+            }
+
+            /// <summary>
+            /// Put datetime encoded as Unix time
+            /// </summary>
+            /// <param name='operations'>
+            /// The operations group for this extension method.
+            /// </param>
+            /// <param name='intBody'>
+            /// </param>
+            /// <param name='cancellationToken'>
+            /// The cancellation token.
+            /// </param>
+            public static async Task PutUnixTimeDateAsync(this IIntModel operations, DateTime intBody, CancellationToken cancellationToken = default(CancellationToken))
+            {
+                await operations.PutUnixTimeDateWithHttpMessagesAsync(intBody, null, cancellationToken).ConfigureAwait(false);
+            }
+
+            /// <summary>
+            /// Get invalid Unix time value
+            /// </summary>
+            /// <param name='operations'>
+            /// The operations group for this extension method.
+            /// </param>
+            public static DateTime? GetInvalidUnixTime(this IIntModel operations)
+            {
+                return Task.Factory.StartNew(s => ((IIntModel)s).GetInvalidUnixTimeAsync(), operations, CancellationToken.None, TaskCreationOptions.None, TaskScheduler.Default).Unwrap().GetAwaiter().GetResult();
+            }
+
+            /// <summary>
+            /// Get invalid Unix time value
+            /// </summary>
+            /// <param name='operations'>
+            /// The operations group for this extension method.
+            /// </param>
+            /// <param name='cancellationToken'>
+            /// The cancellation token.
+            /// </param>
+            public static async Task<DateTime?> GetInvalidUnixTimeAsync(this IIntModel operations, CancellationToken cancellationToken = default(CancellationToken))
+            {
+                using (var _result = await operations.GetInvalidUnixTimeWithHttpMessagesAsync(null, cancellationToken).ConfigureAwait(false))
+                {
+                    return _result.Body;
+                }
+            }
+
+            /// <summary>
+            /// Get null Unix time value
+            /// </summary>
+            /// <param name='operations'>
+            /// The operations group for this extension method.
+            /// </param>
+            public static DateTime? GetNullUnixTime(this IIntModel operations)
+            {
+                return Task.Factory.StartNew(s => ((IIntModel)s).GetNullUnixTimeAsync(), operations, CancellationToken.None, TaskCreationOptions.None, TaskScheduler.Default).Unwrap().GetAwaiter().GetResult();
+            }
+
+            /// <summary>
+            /// Get null Unix time value
+            /// </summary>
+            /// <param name='operations'>
+            /// The operations group for this extension method.
+            /// </param>
+            /// <param name='cancellationToken'>
+            /// The cancellation token.
+            /// </param>
+            public static async Task<DateTime?> GetNullUnixTimeAsync(this IIntModel operations, CancellationToken cancellationToken = default(CancellationToken))
+            {
+                using (var _result = await operations.GetNullUnixTimeWithHttpMessagesAsync(null, cancellationToken).ConfigureAwait(false))
+                {
+                    return _result.Body;
+                }
+            }
+
     }
 }
diff --git a/AutoRest/TestServer/server/routes/int.js b/AutoRest/TestServer/server/routes/int.js
index 2299732ca5ad1..f4acbd7104cd2 100644
--- a/AutoRest/TestServer/server/routes/int.js
+++ b/AutoRest/TestServer/server/routes/int.js
@@ -65,10 +65,27 @@ var integer = function(coverage) {
         } else if (req.params.scenario === 'underflowint64') {
             coverage['getLongUnderflow']++;
             res.status(200).end('-9223372036854775910');
+        } else if (req.params.scenario === 'unixtime') {
+            coverage['getUnixTime']++;
+            res.status(200).end('1460505600');
+        } else if (req.params.scenario === 'invalidunixtime') {
+            coverage['getInvalidUnixTime']++;
+            res.status(200).end('123jkl');
+        } else if (req.params.scenario === 'nullunixtime') {
+            coverage['getNullUnixTime']++;
+            res.status(200).end();
         } else {
             res.status(400).send('Request path must contain true or false');
         }
-
+    });
+    
+    router.put('/unixtime', function(req, res, next) {
+          if (req.body != 1460505600) {
+              utils.send400(res, next, "Did not like the value provided for unixtime in the req " + util.inspect(req.body));
+          } else {
+              coverage['putUnixTime']++;
+              res.status(200).end();
+          }
     });
 }
 
diff --git a/AutoRest/TestServer/swagger/body-integer.json b/AutoRest/TestServer/swagger/body-integer.json
index 00b73a2c2731c..5f321e2981692 100644
--- a/AutoRest/TestServer/swagger/body-integer.json
+++ b/AutoRest/TestServer/swagger/body-integer.json
@@ -251,6 +251,95 @@
           }
         }
       }
+    },
+    "/int/unixtime": {
+      "get": {
+        "operationId": "int_getUnixTime",
+        "description": "Get datetime encoded as Unix time value",
+        "responses": {
+          "200": {
+            "description": "The date value encoded as Unix time",
+            "schema": {
+              "type": "integer",
+              "format": "unixtime"
+            }
+          },
+          "default": {
+            "description": "Unexpected error",
+            "schema": {
+              "$ref": "#/definitions/Error"
+            }
+          }
+        }
+      },
+      "put": {
+        "operationId": "int_putUnixTimeDate",
+        "description": "Put datetime encoded as Unix time",
+        "parameters": [
+          {
+            "name": "intBody",
+            "in": "body",
+            "schema": {
+              "type": "integer",
+              "format": "unixtime"
+            },
+            "required": true
+          }
+        ],
+        "responses": {
+          "200": {
+            "description": "The datetime value encoded as Unix time"
+          },
+          "default": {
+            "description": "Unexpected error",
+            "schema": {
+              "$ref": "#/definitions/Error"
+            }
+          }
+        }
+      }
+    },
+    "/int/invalidunixtime": {
+      "get": {
+        "operationId": "int_getInvalidUnixTime",
+        "description": "Get invalid Unix time value",
+        "responses": {
+          "200": {
+            "description": "The invalid Unix time value",
+            "schema": {
+              "type": "integer",
+              "format": "unixtime"
+            }
+          },
+          "default": {
+            "description": "Unexpected error",
+            "schema": {
+              "$ref": "#/definitions/Error"
+            }
+          }
+        }
+      }
+    },
+    "/int/nullunixtime": {
+      "get": {
+        "operationId": "int_getNullUnixTime",
+        "description": "Get null Unix time value",
+        "responses": {
+          "200": {
+            "description": "The null Unix time value",
+            "schema": {
+              "type": "integer",
+              "format": "unixtime"
+            }
+          },
+          "default": {
+            "description": "Unexpected error",
+            "schema": {
+              "$ref": "#/definitions/Error"
+            }
+          }
+        }
+      }
     }
   },
   "definitions": {
diff --git a/ClientRuntimes/CSharp/Microsoft.Rest.ClientRuntime/Serialization/UnixTimeJsonConverter.cs b/ClientRuntimes/CSharp/Microsoft.Rest.ClientRuntime/Serialization/UnixTimeJsonConverter.cs
index 8f6283b6237ce..fd345541a6de0 100644
--- a/ClientRuntimes/CSharp/Microsoft.Rest.ClientRuntime/Serialization/UnixTimeJsonConverter.cs
+++ b/ClientRuntimes/CSharp/Microsoft.Rest.ClientRuntime/Serialization/UnixTimeJsonConverter.cs
@@ -26,18 +26,18 @@ public class UnixTimeJsonConverter : JsonConverter
         /// </summary>
         /// <param name="input">The Base64Url encoded string</param>
         /// <returns>The byte array represented by the enconded string</returns>
-        private static DateTime FromUnixTime(long? seconds)
+        private static DateTime? FromUnixTime(long? seconds)
         {
             if (seconds.HasValue)
             {
                 return EpochDate.AddSeconds(seconds.Value);
             }
-            return EpochDate;
+            return null;
         }
 
         public override bool CanConvert(Type objectType)
         {
-            if (objectType == typeof(DateTime))
+            if (objectType == typeof(DateTime?) || objectType == typeof(DateTime))
                 return true;
 
             return false;
@@ -45,13 +45,14 @@ public override bool CanConvert(Type objectType)
 
         public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
         {
-            if (objectType != typeof(DateTime))
+            if (objectType != typeof(DateTime?))
             {
                 return serializer.Deserialize(reader, objectType);
             }
             else
             {
                 var value = serializer.Deserialize<long?>(reader);
+
                 if (value.HasValue)
                 {
                     return FromUnixTime(value);