proto int
		err   error
	}
	ch := make(chan result) // unbuffered
	go func() {
		if err := acquireThread(ctx); err != nil {
			ch <- result{err: mapErr(err)}
			return
		}
		defer releaseThread()
		runtime.LockOSThread()
		defer runtime.UnlockOSThread()
		proto, err := getprotobyname(name)
		select {
		case ch <- result{proto: proto, err: err}:
		case <-ctx.Done():
		}
	}()
	select {

			Err:       mapErr(err).Error(),
			IsTimeout: err == context.DeadlineExceeded,
		}
	}

	if ctx.Done() == nil {
		defer releaseThread()
		return blocking()
	}

	type result struct {
		res T
		err error
	}

	res := make(chan result, 1)
	go func() {
		defer releaseThread()
		var r result
		r.res, r.err = blocking()
		res <- r
	}()

	select {
	case r := <-res:
		return r.res, r.err

		threadLimit = make(chan struct{}, concurrentThreadsLimit())
	})
	select {
	case threadLimit <- struct{}{}:
		return nil
	case <-ctx.Done():
		return ctx.Err()
	}
}

func releaseThread() {
	<-threadLimit
}

// buffersWriter is the interface implemented by Conns that support a
// "writev"-like batch write optimization.
// writeBuffers should fully consume and write all chunks from the

      DelayedActionRunnable toRun = new Release(semaphore, countdownInMillis);
      // TODO(cpovirk): automatically fail the test if this thread throws
      Thread releaserThread = new Thread(toRun);
      releaserThread.start();
    }
  }

  private abstract static class DelayedActionRunnable implements Runnable {
    private final long tMinus;

    protected DelayedActionRunnable(long tMinus) {

      DelayedActionRunnable toRun = new Release(semaphore, countdownInMillis);
      // TODO(cpovirk): automatically fail the test if this thread throws
      Thread releaserThread = new Thread(toRun);
      releaserThread.start();
    }
  }

  private abstract static class DelayedActionRunnable implements Runnable {
    private final long tMinus;

    protected DelayedActionRunnable(long tMinus) {