sftp: option SSH_OPTIONS_TIMEOUT does not seems to be supported in blocking mode

I am working on a file transfer client-server application, and I'd like to prevent the client from being blocked if the server doesn't respond as expected.

I tried to setup SSH_OPTIONS_TIMEOUT or the one is microsecond and intentionally block the client on the sftp_open function. And after waiting for N seconds configured, function is not interrupted.

Even if it implies a fatal error on server side it could be useful to be notified as requested on client side to shutdown connection for example.