public Object take() throws InterruptedException, ForceReattemptException {
    throw new UnsupportedOperationException();
    // Currently has no callers.
    // To support this callers need to call release on the returned GatewaySenderEventImpl.
    // Object key = this.eventSeqNumQueue.remove();
    // Object object = null;
    // if (key != null) {
    // object = PartitionRegionHelper
    // .getLocalPrimaryData(getPartitionedRegion()).get(key);
    // /**
    // * TODO: For the time being this is same as peek. To do a batch peek we
    // * need to remove the head key. We will destroy the key once the event is
    // * delivered to the GatewayReceiver.
    // */
    // destroyKey(key);
    // }
    // return object;
  }
It removes the first key from the queue.

@return Returns the value.
geode-core/src/main/java/org/apache/geode/internal/cache/BucketRegionQueue.java