@Override
  public void addMemoryUsageListener(final MemoryUsageListener listener) {
    synchronized (memoryUsageListeners) {
      final MemoryUsageListener[] newMemoryUsageListeners =
          Arrays.copyOf(memoryUsageListeners, memoryUsageListeners.length + 1);
      newMemoryUsageListeners[memoryUsageListeners.length] = listener;
      memoryUsageListeners = newMemoryUsageListeners;
    }
  }
Return the slabId of the slab that contains the given addr.
geode-core/src/main/java/org/apache/geode/internal/offheap/MemoryAllocatorImpl.java