Improve unit tests.

Tests/MQTTnet.Core.Tests/MqttTcpChannel_Tests.cs

@@ -37,10 +37,10 @@ namespace MQTTnet.Tests
                 var clientSocket = new CrossPlatformSocket(AddressFamily.InterNetwork);
                 await clientSocket.ConnectAsync("localhost", 50001, CancellationToken.None);
 
-                await Task.Delay(100, ct.Token);
-
                 var tcpChannel = new MqttTcpChannel(clientSocket.GetStream(), "test", null);
 
+                await Task.Delay(100, ct.Token);
+
                 var buffer = new byte[1];
                 await tcpChannel.ReadAsync(buffer, 0, 1, ct.Token);
 

Tests/MQTTnet.Core.Tests/Server_Tests.cs

@@ -375,7 +375,7 @@ namespace MQTTnet.Tests
                     await c1.PublishAsync(message);
                 }
 
-                await Task.Delay(500);
+                await Task.Delay(3000);
 
                 Assert.AreEqual(2000, receivedMessagesCount);
             }