clientWriter.writePing("Hello".encodeUtf8())
    assertData("898560b420bb28d14cd70f")
  }

  @Test fun serverEmptyPong() {
    serverWriter.writePong(EMPTY)
    assertData("8a00")
  }

  @Test fun clientEmptyPong() {
    clientWriter.writePong(EMPTY)
    assertData("8a8060b420bb")
  }

  @Test fun serverPongWithPayload() {
    serverWriter.writePong("Hello".encodeUtf8())
    assertData("8a0548656c6c6f")

  @Throws(InterruptedException::class)
  fun writePingAndAwaitPong() {
    writePing()
    awaitPong()
  }

  /** For testing: sends a ping to be awaited with [awaitPong]. */
  @Throws(InterruptedException::class)
  fun writePing() {
    this.withLock {
      awaitPingsSent++
    }

    // 0x4f 0x4b 0x6f 0x6b is "OKok".
    writePing(false, AWAIT_PING, 0x4f4b6f6b)
  }

  /** For testing: awaits a pong. */

  /** Send a ping with the supplied [payload]. */
  @Throws(IOException::class)
  fun writePing(payload: ByteString) {
    writeControlFrame(OPCODE_CONTROL_PING, payload)
  }

  /** Send a pong with the supplied [payload]. */
  @Throws(IOException::class)
  fun writePong(payload: ByteString) {
    writeControlFrame(OPCODE_CONTROL_PONG, payload)
  }

  /**

              "${pingIntervalMillis}ms (after ${failedPing - 1} successful ping/pongs)",
          ),
        isWriter = true,
      )
      return
    }

    try {
      writer.writePing(ByteString.EMPTY)
    } catch (e: IOException) {
      failWebSocket(e = e, isWriter = true)
    }
  }

  fun failWebSocket(
    e: Exception,
    response: Response? = null,

    connection.withLock {
      if (!connection.isHealthy(System.nanoTime())) {
        throw ConnectionShutdownException()
      }
    }
    connection.writePing()
    connection.shutdown(ErrorCode.PROTOCOL_ERROR)
    assertThat(connection.openStreamCount()).isEqualTo(1)
    connection.awaitPong() // Prevent the peer from exiting prematurely.

    nextAddress += count
    return (from until nextAddress)
      .map {
        return@map InetAddress.getByAddress(
          Buffer().writeLong(0L).writeLong(it).readByteArray(),
        )
      }
  }

    out.writeByte(100);
    out.writeByte(-100);
    out.writeByte((byte) 200);
    out.writeChar('a');
    out.writeShort((short) -30000);
    out.writeShort((short) 50000);
    out.writeInt(0xCAFEBABE);
    out.writeLong(0xDEADBEEFCAFEBABEL);
    out.writeUTF("Herby Derby");
    out.writeFloat(Float.intBitsToFloat(0xCAFEBABE));
    out.writeDouble(Double.longBitsToDouble(0xDEADBEEFCAFEBABEL));

    out.writeByte(100);
    out.writeByte(-100);
    out.writeByte((byte) 200);
    out.writeChar('a');
    out.writeShort((short) -30000);
    out.writeShort((short) 50000);
    out.writeInt(0xCAFEBABE);
    out.writeLong(0xDEADBEEFCAFEBABEL);
    out.writeUTF("Herby Derby");
    out.writeFloat(Float.intBitsToFloat(0xCAFEBABE));
    out.writeDouble(Double.longBitsToDouble(0xDEADBEEFCAFEBABEL));

   * little-endian byte order.
   *
   * @throws IOException if an I/O error occurs
   */
  @Override
  public void writeLong(long v) throws IOException {
    ((DataOutputStream) out).writeLong(Long.reverseBytes(v));
  }

  /**
   * Writes a {@code short} as specified by {@link DataOutputStream#writeShort(int)}, except using
   * little-endian byte order.
   *

      frameHeader(
        streamId = 0,
        length = 8,
        type = TYPE_PING,
        flags = if (ack) FLAG_ACK else FLAG_NONE,
      )
      sink.writeInt(payload1)
      sink.writeInt(payload2)
      sink.flush()
    }
  }

  /**
   * Tell the peer to stop creating streams and that we last processed `lastGoodStreamId`, or zero
   * if no streams were processed.
   *