assertTrue(queue.add("hi"));
    assertEquals("hi", queue.element());
    assertEquals("hi", queue.peek());
    assertEquals(1, queue.size());
    assertEquals(0, queue.remainingCapacity());

    assertTrue(queue.add("there"));
    assertEquals("there", queue.element());
    assertEquals("there", queue.peek());
    assertEquals(1, queue.size());
    assertEquals(0, queue.remainingCapacity());

    // other threads waiting on take() will also return.
    if (result == DEAD_LETTER) responseQueue.add(DEAD_LETTER)

    return result
  }

  public override fun peek(): MockResponse = responseQueue.peek() ?: failFastResponse ?: super.peek()

  public open fun enqueue(response: MockResponse) {
    responseQueue.add(response)
  }

  public open fun clear() {
    responseQueue.clear()
  }

    return delegate().poll();
  }

  @CanIgnoreReturnValue
  @Override
  @ParametricNullness
  public E remove() {
    return delegate().remove();
  }

  @Override
  public @Nullable E peek() {
    return delegate().peek();
  }

  @Override
  @ParametricNullness
  public E element() {
    return delegate().element();
  }

  /**

    public boolean remove(Object object) {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.remove(object);
    }

    @Override
    public @Nullable E peek() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.peek();
    }

    @Override
    public E element() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.element();
    }

    @Override

	switch t.tok {
	case '\n':
		t.line++
	case '-':
		if s.Peek() == '>' {
			s.Next()
			t.tok = ARR
			return ARR
		}
	case '@':
		if s.Peek() == '>' {
			s.Next()
			t.tok = ROT
			return ROT
		}
	case '<':
		if s.Peek() == '<' {
			s.Next()
			t.tok = LSH
			return LSH
		}
	case '>':
		if s.Peek() == '>' {
			s.Next()
			t.tok = RSH
			return RSH
		}
	}

    return delegate().poll();
  }

  @CanIgnoreReturnValue
  @Override
  @ParametricNullness
  public E remove() {
    return delegate().remove();
  }

  @Override
  public @Nullable E peek() {
    return delegate().peek();
  }

  @Override
  @ParametricNullness
  public E element() {
    return delegate().element();
  }

  /**

        SrvPipePeekResponse peek = resp.getOutputData(SrvPipePeekResponse.class);
        assertNotNull(peek);
        assertEquals(16, resp.getOutputLength());
        // Default zeros
        assertEquals(0, peek.getNamedPipeState());
        assertEquals(0, peek.getReadDataAvailable());
        assertEquals(0, peek.getNumberOfMessages());
        assertEquals(0, peek.getMessageLength());
    }

        Smb2IoctlResponse ioResp = mock(Smb2IoctlResponse.class);
        SrvPipePeekResponse peek = mock(SrvPipePeekResponse.class);
        when(peek.getReadDataAvailable()).thenReturn(7);
        when(ioResp.getOutputData()).thenReturn(peek);

        when(tree.send(any(Smb2IoctlRequest.class), eq(RequestParam.NO_RETRY))).thenReturn(ioResp);

        // Act

 * an HTTP call to a remote server.
 */
interface TrailersSource {
  @Throws(IOException::class)
  fun peek(): Headers? = null

  @Throws(IOException::class)
  fun get(): Headers

  companion object {
    @JvmField
    val EMPTY: TrailersSource =
      object : TrailersSource {
        override fun peek() = Headers.EMPTY

        override fun get() = Headers.EMPTY
      }
  }

  return object : mockwebserver3.Dispatcher() {
    override fun dispatch(request: mockwebserver3.RecordedRequest): mockwebserver3.MockResponse = delegate.dispatch(request.unwrap()).wrap()

    override fun peek(): mockwebserver3.MockResponse = delegate.peek().wrap()

    override fun close() {
      delegate.shutdown()
    }
  }
}

internal fun MockResponse.wrap(): mockwebserver3.MockResponse {