protected void drainClientCqEvents(ClientProxyMembershipID clientId,
      InternalCqQuery cqToClose) {
    _messageQueue.closeClientCq(clientId, cqToClose);
  }
Returns the size of the queue calculated through stats This includes events that have
dispatched but have yet been removed

@return the size of the queue
geode-core/src/main/java/org/apache/geode/internal/cache/tier/sockets/MessageDispatcher.java