@Override
  public void throwIfDistributionStopped() {
    if (shutdownMsgSent) {
      throw new DistributedSystemDisconnectedException(
          "Message distribution has terminated",
          getRootCause());
    }
  }
This thread processes member events as they occur.

@see ClusterDistributionManager.MemberCrashedEvent
@see ClusterDistributionManager.MemberJoinedEvent
@see ClusterDistributionManager.MemberDepartedEvent
geode-core/src/main/java/org/apache/geode/distributed/internal/ClusterDistributionManager.java