public void shutDown() {
      if (logger.isTraceEnabled(DM_VERBOSE)) {
        logger.trace(DM_VERBOSE, "JoinProcessor: shutting down");
      }
      shutDown = true;
      interrupt();
    }
Processes pending membership joins in a dedicated thread. If we processed the joins in the same
thread as the membership handler, then we run the risk of getting deadlocks and such.
geode-core/src/main/java/org/apache/geode/internal/admin/remote/RemoteGfManagerAgent.java