Add deflate compressions options to MqttClientWebSocketOptionsBuilder

Source/MQTTnet/Implementations/MqttWebSocketChannel.cs

@@ -200,6 +200,9 @@ void SetupClientWebSocket(ClientWebSocket clientWebSocket)
                 }
             }
 
+            if (_options.DangerousDeflateOptions != null)
+                clientWebSocket.Options.DangerousDeflateOptions = _options.DangerousDeflateOptions;
+
             // Only set the value if it is actually true. This property is not supported on all platforms
             // and will throw a _PlatformNotSupported_ (i.e. WASM) exception when being used regardless of the actual value.
             if (_options.UseDefaultCredentials)

Source/MQTTnet/Options/MqttClientWebSocketOptions.cs

@@ -12,6 +12,7 @@ namespace MQTTnet;
 public sealed class MqttClientWebSocketOptions : IMqttClientChannelOptions
 {
     public CookieContainer CookieContainer { get; set; }
+    public WebSocketDeflateOptions DangerousDeflateOptions { get; set; }
 
     public ICredentials Credentials { get; set; }
 

Source/MQTTnet/Options/MqttClientWebSocketOptionsBuilder.cs

@@ -5,6 +5,7 @@
 using System;
 using System.Collections.Generic;
 using System.Net;
+using System.Net.WebSockets;
 
 namespace MQTTnet;
 
@@ -23,6 +24,18 @@ public MqttClientWebSocketOptionsBuilder WithCookieContainer(CookieContainer coo
         return this;
     }
 
+    /// <summary>
+    /// Allows the client to negotiate deflate compression on every message, by using the permessage-deflate WebSocket extension.
+    /// This adds the Sec-WebSocket-Extensions: permessage-deflate; client_max_window_bits header.
+    /// </summary>
+    /// <param name="dangerousDeflateOptions"></param>
+    /// <returns></returns>
+    public MqttClientWebSocketOptionsBuilder WithDangerousDeflateOptions(WebSocketDeflateOptions dangerousDeflateOptions)
+    {
+        _webSocketOptions.DangerousDeflateOptions = dangerousDeflateOptions;
+        return this;
+    }
+
     public MqttClientWebSocketOptionsBuilder WithCookieContainer(ICredentials credentials)
     {
         _webSocketOptions.Credentials = credentials;