// package-private
  int poll(int events, long timeout) throws IOException {
    assert Thread.holdsLock(blockingLock()) && !isBlocking();

    synchronized (readLock) {
      int n = 0;
      try {
        begin();
        synchronized (stateLock) {
          if (!isOpen()) return 0;
          readerThread = NativeThread.current();
        }
        n = Net.poll(fd, events, timeout);
      } finally {
        readerThread = 0;
        end(n > 0);
      }
      return n;
    }
  }