public synchronized void cancelAction(String action) {
    if (!isShuttingDown) {
      this.tryCancelScheduledAction(action);
    }
  }
Performs the following operations in sequential order.
<ul>
   <li> Makes best effort to cancel any existing task in task queue associated with the action.</li>
   <li> Schedules the incoming action for later execution and records its future.</li>
</ul>

@param actionName the name of scheduleable action.
@param delayInMillis the time from now to delay execution.
@param runnable the action to execute.
samza-core/src/main/java/org/apache/samza/zk/ScheduleAfterDebounceTime.java