@Override
  public List<InternalDistributedMember> getRecipients() {
    if (recipients == null
        || recipients.size() == 1 && recipients.get(0) == ALL_RECIPIENTS) {
      return ALL_RECIPIENTS_LIST;
    }

    return recipients;
  }
Sets the intended recipient of the message. If recipient set contains
Message.ALL_RECIPIENTS
then the message will be sent to all distribution managers.
geode-core/src/main/java/org/apache/geode/distributed/internal/DistributionMessage.java