Merge branch 'master' into feature/low_level_client

Tests/MQTTnet.Core.Tests/Server_Tests.cs

@@ -1050,6 +1050,7 @@ namespace MQTTnet.Tests
                 Assert.AreEqual("c", flow);
 
                 // dc
+                // Connect client with same client ID. Should disconnect existing client.
                 var c2 = await testEnvironment.ConnectClientAsync(clientOptionsBuilder);
 
                 c2.UseApplicationMessageReceivedHandler(_ =>
@@ -1075,7 +1076,6 @@ namespace MQTTnet.Tests
                 flow = string.Join(string.Empty, events);
                 Assert.AreEqual("cdcr", flow);
 
-
                 // nothing
 
                 Assert.AreEqual(false, c1.IsConnected);