@Override public final void sample(){
  long count=_count.get();
  long lastCount=_lastCount.getAndSet(count);
  _value=count - lastCount;
}

@ Override public final void sample ( ) { long count = _count . get ( ) ; long lastCount = _lastCount . getAndSet ( count ) ; _value = count - lastCount ; }
return the probe ' s next sample .
