Best strategy to detect that the connection is down?

Hi,

it looks like the method SSHClient.isConnected() will not detect that the server is down after an initial connection is established and afterward the server is shut down.

I have tried even to call SftpClient.ls("/") and surprisingly I get an answer even if the server is not running.

I have also set the timeout to a lower value but still no improvement
sftpClient.getSFTPEngine().setTimeoutMs(3000);

What is the best approach to recognize when the connection is down?

Thank you!