private InternalDistributedMember nextAppropriateResponder() {
    if (responseQueue != null && responseQueue.size() > 0) {
      return (InternalDistributedMember) responseQueue.remove(0);
    } else {
      return null;
    }
  }
Return the next responder on the responseQueue, or null if empty
geode-core/src/main/java/org/apache/geode/internal/cache/SearchLoadAndWriteProcessor.java