code: function preconnect(user, sshKeyPath, ipaddress, cb, pollCount) {
    if (pollCount === undefined) {
      pollCount = 0;
    }
  
    logger.info({
      user: user,
      identityFile: sshKeyPath,
      ipAddress: ipaddress
    }, 'waiting for connectivity');
  
    portscanner.checkPortStatus(22, ipaddress, function(err, status) {
      if (status === 'closed') {
        if (pollCount > MAX_POLLS) {
          pollCount = 0;
          cb('timeout exceeded - unable to connect to: ' + ipaddress);
        }
        else {
          pollCount = pollCount + 1;
          setTimeout(function() { preconnect(user, sshKeyPath, ipaddress, cb, pollCount); }, POLL_INTERVAL);
        }
      }
      else if (status === 'open') {
        pollCount = 0;
        sshCheck.check(ipaddress, user, sshKeyPath, null, function(err) {
          cb(err);
        });
      }
    });
  }
docs: preconnect in the case that ssh multiplexing is operative