code: public boolean removeStickyEvent(Object event) {
          synchronized (stickyEvents) {
              Class<?> eventType = event.getClass();
              Object existingEvent = stickyEvents.get(eventType);
              if (event.equals(existingEvent)) {
                  stickyEvents.remove(eventType);
                  return true;
              } else {
                  return false;
              }
          }
      }
docs: Removes the sticky event if it equals to the given event.
  
  @return true if the events matched and the sticky event was removed.