@Override
  public void shutdownMessageReceived(ID id, String reason) {
    if (logger.isDebugEnabled()) {
      logger.debug("Membership: recording shutdown status of {}", id);
    }
    shutdownMembersWriteLock.lock();
    try {
      shutdownMembers.add(id);
      services.getJoinLeave().memberShutdown(id, reason);
    } finally {
      shutdownMembersWriteLock.unlock();
    }
  }
in order to avoid split-brain occurring when a member is shutting down due to race conditions
in view management we add it as a shutdown member when we receive a shutdown message. This is
not the same as a SHUNNED member.
geode-membership/src/main/java/org/apache/geode/distributed/internal/membership/gms/GMSMembership.java