fix: adjust to NewClient error handling

client.go

@@ -30,7 +30,10 @@ import (
 // FindServers returns the servers known to a server or discovery server.
 func FindServers(ctx context.Context, endpoint string, opts ...Option) ([]*ua.ApplicationDescription, error) {
 	opts = append(opts, AutoReconnect(false))
-	c := NewClient(endpoint, opts...)
+	c, err := NewClient(endpoint, opts...)
+	if err != nil {
+		return nil, err
+	}
 	if err := c.Dial(ctx); err != nil {
 		return nil, err
 	}
@@ -45,7 +48,10 @@ func FindServers(ctx context.Context, endpoint string, opts ...Option) ([]*ua.Ap
 // FindServersOnNetwork returns the servers known to a server or discovery server. Unlike FindServers, this service is only implemented by discovery servers.
 func FindServersOnNetwork(ctx context.Context, endpoint string, opts ...Option) ([]*ua.ServerOnNetwork, error) {
 	opts = append(opts, AutoReconnect(false))
-	c := NewClient(endpoint, opts...)
+	c, err := NewClient(endpoint, opts...)
+	if err != nil {
+		return nil, err
+	}
 	if err := c.Dial(ctx); err != nil {
 		return nil, err
 	}