@Override
  public void removeAsyncEventQueueId(String asyncEventQueueId) {
    getAsyncEventQueueIds().remove(asyncEventQueueId);
    getVisibleAsyncEventQueueIds().remove(asyncEventQueueId);
    setAllGatewaySenderIds();
  }
Use ONLY imSync for IndexManager get and set.

@return {@link IndexManager} lock.
geode-core/src/main/java/org/apache/geode/internal/cache/AbstractRegion.java