if (source.isEmpty()) {
        throw PermittedMetaException.NSEE;
      }

      destination.push(source.pop());
      stackWithLastReturnedElementAtTop = destination;
      return destination.peek();
    }

    private void throwIfInvalid(IteratorFeature methodFeature) {
      if (!features.contains(methodFeature)) {
        if (stackWithLastReturnedElementAtTop == null) {

   * a modest limit on `byteCount`, such as 1 MiB.
   */
  @Throws(IOException::class)
  fun peekBody(byteCount: Long): ResponseBody {
    val peeked = body.source().peek()
    val buffer = Buffer()
    peeked.request(byteCount)
    buffer.write(peeked, minOf(byteCount, peeked.buffer.size))
    return buffer.asResponseBody(body.contentType(), buffer.size)
  }

    monitor.enterWhen(notEmpty);
    try {
      return extract();
    } finally {
      monitor.leave();
    }
  }

  @CanIgnoreReturnValue
  @Override
  public @Nullable E peek() {
    final Monitor monitor = this.monitor;
    if (monitor.enterIf(notEmpty)) {
      try {
        return items[takeIndex];
      } finally {
        monitor.leave();
      }
    } else {

      while (peekingItr.hasNext()) {
        Range<C> range = peekingItr.next();
        while (peekingItr.hasNext()) {
          Range<C> nextRange = peekingItr.peek();
          if (range.isConnected(nextRange)) {
            checkArgument(
                range.intersection(nextRange).isEmpty(),
                "Overlapping ranges not permitted but found %s overlapping %s",

      drainRecencyQueue();

      ReferenceEntry<K, V> e;
      while ((e = writeQueue.peek()) != null && map.isExpired(e, now)) {
        if (!removeEntry(e, e.getHash(), RemovalCause.EXPIRED)) {
          throw new AssertionError();
        }
      }
      while ((e = accessQueue.peek()) != null && map.isExpired(e, now)) {
        if (!removeEntry(e, e.getHash(), RemovalCause.EXPIRED)) {

  fun dispatcherFromMockWebServer() {
    val dispatcher =
      object : okhttp3.mockwebserver.Dispatcher() {
        override fun dispatch(request: RecordedRequest): MockResponse = TODO()

        override fun peek(): MockResponse = TODO()

        override fun shutdown() = TODO()
      }
  }

  @Test
  fun dns() {
    var dns: Dns = Dns { TODO() }

    val system: Dns = Dns.SYSTEM
  }

		}
	}
}

func Test_metacacheReader_peek(t *testing.T) {
	r := loadMetacacheSample(t)
	defer r.Close()
	for i, want := range loadMetacacheSampleNames {
		got, err := r.peek()
		if err == io.EOF {
			break
		}
		if err != nil {
			t.Fatal(err)
		}
		if got.name != want {
			t.Errorf("entry %d, want %q, got %q", i, want, got.name)
		}
		gotObj, err := r.next()

    public boolean offer(E e) {
      synchronized (mutex) {
        return delegate().offer(e);
      }
    }

    @Override
    @CheckForNull
    public E peek() {
      synchronized (mutex) {
        return delegate().peek();
      }
    }

    @Override
    @CheckForNull
    public E poll() {
      synchronized (mutex) {
        return delegate().poll();
      }
    }

    public boolean offer(E e) {
      synchronized (mutex) {
        return delegate().offer(e);
      }
    }

    @Override
    @CheckForNull
    public E peek() {
      synchronized (mutex) {
        return delegate().peek();
      }
    }

    @Override
    @CheckForNull
    public E poll() {
      synchronized (mutex) {
        return delegate().poll();
      }
    }

            } catch (e: IOException) {
              throw RuntimeException(e)
            }
          }
          return result
        }

        override fun peek(): MockResponse = queueDispatcher.peek()

        override fun shutdown() {
          queueDispatcher.shutdown()
        }
      }
    client =
      client.newBuilder()
        .proxy(server.toProxyAddress())