'Add the callback_method indirectly to the IOLoop timer to fire
after deadline seconds. Returns the timer handle.
:param int deadline: The number of seconds to wait to call callback
:param method callback_method: The callback method
:param callback_timeout: Whether timeout kwarg is passed on callback
:type callback_timeout: boolean
:param kwargs callback_kwargs: additional kwargs to pass on callback
:rtype: timer instance handle.'

def add_timeout(self, deadline, callback_method, callback_timeout=False, **callback_kwargs):

    LOGGER.debug('deadline:    %s', deadline)
    timer = self._get_timer(deadline)
    self._active_timers[timer] = (callback_method, callback_timeout, callback_kwargs)
    timer.start()
    return timer
