Add new options for _MqttClientOptionsBuilder_.

Build/MQTTnet.nuspec

@@ -14,6 +14,7 @@
 * [Core] Fixed missing properties from PUBLISH packet in _MqttApplicationMessage_ (thanks to @pcbing).
 * [Core] Fixed wrong encoding of PUBREL and PUBCOMP packets for MQTTv5 (thanks to @perphilipp).
 * [Client] Added the authentication result to the disconnected handler (only set when connecting failed).
+* [Client] Added new overloads for _MqttClientOptionsBuilder_.
 * [Server] Fixed a bug which returns wrong flag for existing session in CONNACK packet (thanks to @avengerstark).
 * [nuget] .NET Framework builds are now using 4.5.2 or 4.6.1 builds instead of netstandard 2.0.
     </releaseNotes>

Source/MQTTnet/Client/Options/MqttClientOptionsBuilder.cs

@@ -136,6 +136,16 @@ namespace MQTTnet.Client.Options
             return this;
         }
 
+        public MqttClientOptionsBuilder WithTcpServer(Action<MqttClientTcpOptions> optionsBuilder)
+        {
+            if (optionsBuilder == null) throw new ArgumentNullException(nameof(optionsBuilder));
+
+            _tcpOptions = new MqttClientTcpOptions();
+            optionsBuilder.Invoke(_tcpOptions);
+
+            return this;
+        }
+
         public MqttClientOptionsBuilder WithProxy(string address, string username = null, string password = null, string domain = null, bool bypassOnLocal = false, string[] bypassList = null)
         {
             _proxyOptions = new MqttClientWebSocketProxyOptions
@@ -151,6 +161,15 @@ namespace MQTTnet.Client.Options
             return this;
         }
 
+        public MqttClientOptionsBuilder WithProxy(Action<MqttClientWebSocketProxyOptions> optionsBuilder)
+        {
+            if (optionsBuilder == null) throw new ArgumentNullException(nameof(optionsBuilder));
+
+            _proxyOptions = new MqttClientWebSocketProxyOptions();
+            optionsBuilder(_proxyOptions);
+            return this;
+        }
+
         public MqttClientOptionsBuilder WithWebSocketServer(string uri, MqttClientOptionsBuilderWebSocketParameters parameters = null)
         {
             _webSocketOptions = new MqttClientWebSocketOptions
@@ -163,9 +182,19 @@ namespace MQTTnet.Client.Options
             return this;
         }
 
+        public MqttClientOptionsBuilder WithWebSocketServer(Action<MqttClientWebSocketOptions> optionsBuilder)
+        {
+            if (optionsBuilder == null) throw new ArgumentNullException(nameof(optionsBuilder));
+
+            _webSocketOptions = new MqttClientWebSocketOptions();
+            optionsBuilder.Invoke(_webSocketOptions);
+
+            return this;
+        }
+
         public MqttClientOptionsBuilder WithTls(MqttClientOptionsBuilderTlsParameters parameters)
         {
-            _tlsParameters = parameters ?? throw new ArgumentNullException(nameof(parameters));
+            _tlsParameters = parameters;
             return this;
         }
 
@@ -174,6 +203,15 @@ namespace MQTTnet.Client.Options
             return WithTls(new MqttClientOptionsBuilderTlsParameters { UseTls = true });
         }
 
+        public MqttClientOptionsBuilder WithTls(Action<MqttClientOptionsBuilderTlsParameters> optionsBuilder)
+        {
+            if (optionsBuilder == null) throw new ArgumentNullException(nameof(optionsBuilder));
+
+            _tlsParameters = new MqttClientOptionsBuilderTlsParameters();
+            optionsBuilder(_tlsParameters);
+            return this;
+        }
+
         public IMqttClientOptions Build()
         {
             if (_tcpOptions == null && _webSocketOptions == null)