Use latest language features (#2176)

* Make use of language features line AsyncDispose, init etc.

* Fix build errors

* Improve Unit Tests

* Improve Unit Tests

* Improve Unit Tests

* Update samples

* Remove obsolete benchmarks

* Code cleanup

* Improve unit tests

* Improve Unit Tests

* Fix Unit Tests

* Improve Unit Tests

* Improve Unit Tests

* Restore unit tests

* Exclude load tests from unit tests

Source/MQTTnet.Server/Internal/EnqueueDataPacketResult.cs

@@ -2,11 +2,10 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-namespace MQTTnet.Server.Internal
+namespace MQTTnet.Server.Internal;
+
+public enum EnqueueDataPacketResult
 {
-    public enum EnqueueDataPacketResult
-    {
-        Enqueued,
-        Dropped
-    }
+    Enqueued,
+    Dropped
 }