@Override
  public void close() {
    synchronized (lock) {
      ids = null; // set null to prevent memory leak after closure!
    }
  }
Used to asynchronously disconnect an InternalDistributedSystem when we run out of off-heap
memory. If the STAY_CONNECTED_ON_OUTOFOFFHEAPMEMORY_PROPERTY sys prop is set to true then this
listener will not disconnect.
geode-core/src/main/java/org/apache/geode/internal/offheap/DisconnectingOutOfOffHeapMemoryListener.java