Remove useless sempahore object

Frameworks/MQTTnet.NetStandard/Adapter/MqttChannelAdapter.cs

@@ -19,7 +19,6 @@ namespace MQTTnet.Adapter
         private const int ReadBufferSize = 4096;  // TODO: Move buffer size to config
 
         private bool _isDisposed;
-        private readonly SemaphoreSlim _semaphore = new SemaphoreSlim(1, 1);
         private readonly IMqttNetLogger _logger;
         private readonly IMqttChannel _channel;
 
@@ -232,7 +231,6 @@ namespace MQTTnet.Adapter
         public void Dispose()
         {
             _isDisposed = true;
-            _semaphore?.Dispose();
             _channel?.Dispose();
         }
 

MQTTnet.sln

@@ -39,6 +39,9 @@ EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "MQTTnet.Extensions.Rpc", "Extensions\MQTTnet.Extensions.Rpc\MQTTnet.Extensions.Rpc.csproj", "{C444E9C8-95FA-430E-9126-274129DE16CD}"
 EndProject
 Global
+	GlobalSection(Performance) = preSolution
+		HasPerformanceSessions = true
+	EndGlobalSection
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
 		Debug|ARM = Debug|ARM