diff --git a/google-cloud-clients/google-cloud-firestore/src/main/java/com/google/cloud/firestore/v1/FirestoreClient.java b/google-cloud-clients/google-cloud-firestore/src/main/java/com/google/cloud/firestore/v1/FirestoreClient.java
index 857ce007cb94..e5cc08d0913c 100644
--- a/google-cloud-clients/google-cloud-firestore/src/main/java/com/google/cloud/firestore/v1/FirestoreClient.java
+++ b/google-cloud-clients/google-cloud-firestore/src/main/java/com/google/cloud/firestore/v1/FirestoreClient.java
@@ -30,6 +30,7 @@
 import com.google.api.pathtemplate.PathTemplate;
 import com.google.cloud.firestore.v1.stub.FirestoreStub;
 import com.google.cloud.firestore.v1.stub.FirestoreStubSettings;
+import com.google.common.util.concurrent.MoreExecutors;
 import com.google.firestore.v1.BatchGetDocumentsRequest;
 import com.google.firestore.v1.BatchGetDocumentsResponse;
 import com.google.firestore.v1.BeginTransactionRequest;
@@ -1143,7 +1144,8 @@ public static ApiFuture<ListDocumentsPagedResponse> createAsync(
             public ListDocumentsPagedResponse apply(ListDocumentsPage input) {
               return new ListDocumentsPagedResponse(input);
             }
-          });
+          },
+          MoreExecutors.directExecutor());
     }
 
     private ListDocumentsPagedResponse(ListDocumentsPage page) {
@@ -1223,7 +1225,8 @@ public static ApiFuture<ListCollectionIdsPagedResponse> createAsync(
             public ListCollectionIdsPagedResponse apply(ListCollectionIdsPage input) {
               return new ListCollectionIdsPagedResponse(input);
             }
-          });
+          },
+          MoreExecutors.directExecutor());
     }
 
     private ListCollectionIdsPagedResponse(ListCollectionIdsPage page) {
diff --git a/google-cloud-clients/google-cloud-firestore/src/main/java/com/google/cloud/firestore/v1beta1/FirestoreClient.java b/google-cloud-clients/google-cloud-firestore/src/main/java/com/google/cloud/firestore/v1beta1/FirestoreClient.java
index ce92bacdefb1..f0e2e21eb346 100644
--- a/google-cloud-clients/google-cloud-firestore/src/main/java/com/google/cloud/firestore/v1beta1/FirestoreClient.java
+++ b/google-cloud-clients/google-cloud-firestore/src/main/java/com/google/cloud/firestore/v1beta1/FirestoreClient.java
@@ -30,6 +30,7 @@
 import com.google.api.pathtemplate.PathTemplate;
 import com.google.cloud.firestore.v1beta1.stub.FirestoreStub;
 import com.google.cloud.firestore.v1beta1.stub.FirestoreStubSettings;
+import com.google.common.util.concurrent.MoreExecutors;
 import com.google.firestore.v1beta1.BatchGetDocumentsRequest;
 import com.google.firestore.v1beta1.BatchGetDocumentsResponse;
 import com.google.firestore.v1beta1.BeginTransactionRequest;
@@ -1143,7 +1144,8 @@ public static ApiFuture<ListDocumentsPagedResponse> createAsync(
             public ListDocumentsPagedResponse apply(ListDocumentsPage input) {
               return new ListDocumentsPagedResponse(input);
             }
-          });
+          },
+          MoreExecutors.directExecutor());
     }
 
     private ListDocumentsPagedResponse(ListDocumentsPage page) {
@@ -1223,7 +1225,8 @@ public static ApiFuture<ListCollectionIdsPagedResponse> createAsync(
             public ListCollectionIdsPagedResponse apply(ListCollectionIdsPage input) {
               return new ListCollectionIdsPagedResponse(input);
             }
-          });
+          },
+          MoreExecutors.directExecutor());
     }
 
     private ListCollectionIdsPagedResponse(ListCollectionIdsPage page) {
diff --git a/google-cloud-clients/google-cloud-firestore/synth.metadata b/google-cloud-clients/google-cloud-firestore/synth.metadata
index 3df6ec3fab02..d655db71d4b2 100644
--- a/google-cloud-clients/google-cloud-firestore/synth.metadata
+++ b/google-cloud-clients/google-cloud-firestore/synth.metadata
@@ -1,19 +1,19 @@
 {
-  "updateTime": "2019-03-01T08:44:26.233377Z",
+  "updateTime": "2019-03-06T08:44:01.706383Z",
   "sources": [
     {
       "generator": {
         "name": "artman",
-        "version": "0.16.14",
-        "dockerImage": "googleapis/artman@sha256:f3d61ae45abaeefb6be5f228cda22732c2f1b00fb687c79c4bd4f2c42bb1e1a7"
+        "version": "0.16.15",
+        "dockerImage": "googleapis/artman@sha256:9caadfa59d48224cba5f3217eb9d61a155b78ccf31e628abef385bc5b7ed3bd2"
       }
     },
     {
       "git": {
         "name": "googleapis",
         "remote": "https://github.com/googleapis/googleapis.git",
-        "sha": "41d72d444fbe445f4da89e13be02078734fb7875",
-        "internalRef": "236230004"
+        "sha": "856117505ff9075b3e9c0b5674113667b6cf9e00",
+        "internalRef": "236931378"
       }
     }
   ],