@Override
  public void updateMemoryUsed(final long bytesUsed) {
    final boolean willSendEvent = mightSendEvent(bytesUsed);
    final OffHeapMemoryMonitorObserver _testHook = testHook;
    if (_testHook != null) {
      _testHook.beginUpdateMemoryUsed(bytesUsed, willSendEvent);
    }
    if (!willSendEvent) {
      return;
    }
    offHeapMemoryUsageListener.deliverEvent();
    if (_testHook != null) {
      _testHook.afterNotifyUpdateMemoryUsed(bytesUsed);
    }
  }
Called at the beginning of updateStateAndSendEvent.

@param bytesUsed the number of bytes of off-heap memory currently used
@param willSendEvent true if an event will be sent to the OffHeapMemoryUsageListener.
geode-core/src/main/java/org/apache/geode/internal/cache/control/OffHeapMemoryMonitor.java