assertEquals(
        "next() should still return first element after peeking", "A", peekingIterator.next());

    assertEquals("Should be able to peek() at middle element", "B", peekingIterator.peek());
    assertEquals(
        "Should be able to peek() middle element multiple times", "B", peekingIterator.peek());
    assertEquals(

   *
   * @throws IOException if the trailers cannot be loaded, such as if the network connection is
   *     dropped.
   */
  @Throws(IOException::class)
  fun peekTrailers(): Headers? = trailersSource.peek()

  /**
   * Peeks up to [byteCount] bytes from the response body and returns them as a new response
   * body. If fewer than [byteCount] bytes are in the response body, the full response body is

          chunked = true
        }
      }

      val peek = dispatcher.peek()
      for (response in peek.informationalResponses) {
        writeHttpResponse(socket, response)
      }

      val requestBodySink =
        requestBody
          .withThrottlingAndSocketEffect(
            policy = peek,
            socketEffect = peek.onRequestBody,
            expectedByteCount = contentLength,

            }
          }
        };

    assertEquals(0, (int) iter.peek());
    assertEquals(0, (int) iter.peek());
    assertTrue(iter.hasNext());
    assertEquals(0, (int) iter.peek());
    assertEquals(0, (int) iter.next());

    assertEquals(1, (int) iter.peek());
    assertEquals(1, (int) iter.next());

    /*
     * We test peek() after various calls to make sure that one bad call doesn't interfere with its

        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

        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());
    }

    assertEquals(3, (int) mmHeap.pollLast());
    assertEquals(1, (int) mmHeap.peek());
    assertEquals(2, (int) mmHeap.peekLast());
    assertEquals(2, (int) mmHeap.pollLast());
    assertEquals(1, (int) mmHeap.peek());
    assertEquals(1, (int) mmHeap.peekLast());
    assertEquals(1, (int) mmHeap.pollLast());
    assertNull(mmHeap.peek());
    assertNull(mmHeap.peekLast());
    assertNull(mmHeap.pollLast());
  }

                object : TrailersSource {
                  override fun peek() = exchange.peekTrailers()

                  override fun get(): Headers {
                    val source = responseBody.source()
                    if (source.isOpen) {
                      source.skipAll()
                    }
                    return peek() ?: error("null trailers after exhausting response body?!")
                  }

     * This stream class is unbuffered. Therefore this method will always
     * return 0 for streams connected to regular files. However, a
     * stream created from a Named Pipe this method will query the server using a
     * "peek named pipe" operation and return the number of available bytes
     * on the server.
     */
    @Override
    public int available() throws IOException {

}

func (b *Reader) readErr() error {
	err := b.err
	b.err = nil
	return err
}

// Peek returns the next n bytes without advancing the reader. The bytes stop
// being valid at the next read call. If necessary, Peek will read more bytes
// into the buffer in order to make n bytes available. If Peek returns fewer
// than n bytes, it also returns an error explaining why the read is short.