code: def update_timer(self, timer, action, usecs):
          
          if action == PYCBC_EVACTION_WATCH:
              timer.schedule(usecs, self.reactor)
  
          elif action == PYCBC_EVACTION_UNWATCH:
              timer.cancel()
  
          elif action == PYCBC_EVACTION_CLEANUP:
              timer.cleanup()
docs: Called by libcouchbase to add/remove timers