private void addAllMembershipListener(MembershipListener l) {
    synchronized (allMembershipListenersLock) {
      Set<MembershipListener> newAllMembershipListeners =
          new HashSet<>(allMembershipListeners);
      newAllMembershipListeners.add(l);
      allMembershipListeners = newAllMembershipListeners;
    }
  }
Adds a <code>MembershipListener</code> to this distribution manager.
geode-core/src/main/java/org/apache/geode/distributed/internal/ClusterDistributionManager.java