fix ca1508

new false positives.

https://learn.microsoft.com/en-us/dotnet/fundamentals/code-analysis/quality-rules/ca1508

Author: mus65

src/Renci.SshNet/Channels/ChannelDirectTcpip.cs

@@ -124,10 +124,12 @@ private void CloseSocket()
 
             lock (_socketLock)
             {
+#pragma warning disable CA1508 // Avoid dead conditional code
                 if (_socket is null)
                 {
                     return;
                 }
+#pragma warning restore CA1508 // Avoid dead conditional code
 
                 // closing a socket actually disposes the socket, so we can safely dereference
                 // the field to avoid entering the lock again later
@@ -293,11 +295,13 @@ protected override void Dispose(bool disposing)
                     lock (_socketLock)
                     {
                         var socket = _socket;
+#pragma warning disable CA1508 // Avoid dead conditional code
                         if (socket != null)
                         {
                             _socket = null;
                             socket.Dispose();
                         }
+#pragma warning restore CA1508 // Avoid dead conditional code
                     }
                 }
 

src/Renci.SshNet/Channels/ChannelForwardedTcpip.cs

@@ -164,11 +164,13 @@ private void CloseSocket()
             lock (_socketShutdownAndCloseLock)
             {
                 var socket = _socket;
+#pragma warning disable CA1508 // Avoid dead conditional code
                 if (socket != null)
                 {
                     _socket = null;
                     socket.Dispose();
                 }
+#pragma warning restore CA1508 // Avoid dead conditional code
             }
         }
 

src/Renci.SshNet/Sftp/SftpFileStream.cs

@@ -1065,6 +1065,7 @@ protected override void Dispose(bool disposing)
                 {
                     lock (_lock)
                     {
+#pragma warning disable CA1508 // Avoid dead conditional code
                         if (_session != null)
                         {
                             _canRead = false;
@@ -1088,6 +1089,7 @@ protected override void Dispose(bool disposing)
 
                             _session = null;
                         }
+#pragma warning restore CA1508 // Avoid dead conditional code
                     }
                 }
             }