@Override
  public void close() {
    agent.removeJoinLeaveListener(this);

    synchronized (this) {
      if (isClosed) {
        return;
      }

      isClosed = true;

      if (dsHealthMonitor != null) {
        dsHealthMonitor.stop();
        dsHealthMonitor = null;
      }

      try {
        for (final Object value : hostMembers.values()) {
          List members = (List) value;
          for (final Object o : members) {
            GemFireVM member = (GemFireVM) o;
            member.removeHealthListener();
          }
        }
      } catch (CancelException e) {
        // if the DS is disconnected, stop trying to distribute to other members
      }

      hostConfigs.clear();
      hostMembers.clear();
      okayHealth.clear();
      poorHealth.clear();
    }
  }
Tells the members of the distributed system that we are no longer interested in monitoring
their health.

@see GemFireVM#removeHealthListener
geode-core/src/main/java/org/apache/geode/admin/internal/GemFireHealthImpl.java