public static int getMessageRPId() {
    int result = 0;
    Object v = messageId.get();
    if (v != null) {
      result = (Integer) v;
    }
    return result;
  }
Returns the reply processor id for the message currently being read. Returns 0 if no id exists.
geode-core/src/main/java/org/apache/geode/distributed/internal/ReplyProcessor21.java