* close the socket as soon as this frame has been written; otherwise the peer stays open until
   * explicitly closed.
   */
  fun truncateLastFrame(length: Int): Http2Writer {
    val lastFrame = outFrames.removeAt(outFrames.size - 1)
    require(length < bytesOut.size - lastFrame.start)

    // Move everything from bytesOut into a new buffer.

    peer.acceptFrame() // ACK
    peer.acceptFrame() // SYN_STREAM
    peer.sendFrame().headers(false, 3, headerEntries("a", "android"))
    peer.sendFrame().data(false, 3, data(1024), 1024)
    peer.truncateLastFrame(8 + 100)
    peer.play()

    // Play it back.
    val connection = connect(peer)
    val stream = connection.newStream(headerEntries("b", "banana"), false)