public static void lockAndFlushToOthers(RegionEventImpl regionEvent,
      Set<InternalDistributedMember> recipients) {
    DistributedClearOperation dco = new DistributedClearOperation(
        DistributedClearOperation.OperationType.OP_LOCK_FOR_CLEAR, regionEvent, null, recipients);
    dco.distribute();
  }
obtain locks on version generation in other members have them do a state-flush back to this
member
geode-core/src/main/java/org/apache/geode/internal/cache/DistributedClearOperation.java