void removeEQ(Object o){
  final ReentrantLock lock=this.lock;
  lock.lock();
  try {
    for (Iterator<E> it=q.iterator(); it.hasNext(); ) {
      if (o == it.next()) {
        it.remove();
        break;
      }
    }
  }
  finally {
    lock.unlock();
  }
}

void removeEQ ( Object o ) { final ReentrantLock lock = this . lock ; lock . lock ( ) ; try { for ( Iterator < E > it = q . iterator ( ) ; it . hasNext ( ) ; ) { if ( o == it . next ( ) ) { it . remove ( ) ; break ; } } } finally { lock . unlock ( ) ; } }
identity - based version for use in itr . remove
