Unhandled Exception under Xamarin iOS

I'm using ssh.net in a Xamarin iOS application. When connecting to a sftp server with the iOS 's wifi turn off. I got this exception:
Unhandled Exception:
System.ObjectDisposedException: Safe handle has been closed occurred.
I debug the source code and found out that's because under Xamarin iOS
socket.ConnectAsync(args) return false when wifi is turned off.
SocketAbstraction.cs line 63 if (socket.ConnectAsync(args))
Then it run line 83 connectCompleted.Dispose();
At last function ConnectCompleted was called , where the exception occurred.

If I moved line 83 connectCompleted.Dispose() into below if statement like this:

       if (args.SocketError != SocketError.Success)
        {
            var socketError = (int) args.SocketError;

            // dispose Socket
            socket.Dispose();
            // dispose SocketAsyncEventArgs
            args.Dispose();

            // dispose ManualResetEvent
            connectCompleted.Dispose();

            throw new SocketException(socketError);
        }

then this bug is fixed.

Beginne in SocketAbstraction.cs ungefähr bei Zeile 63, wo socket.ConnectAsync(args) behandelt wird, und bei Zeile 83, wo connectCompleted verworfen wird. Reproduziere die Xamarin iOS SFTP-Verbindung bei deaktiviertem WLAN und verfolge ConnectCompleted. Erledigt ist die Aufgabe, wenn die fehlgeschlagene Verbindung den erwarteten Socket-Fehler ohne eine ObjectDisposedException auslöst.