}
  }

  @Test fun pingRoundTrip() {
    val expectedPayload1 = 7
    val expectedPayload2 = 8
    writeMedium(frame, 8) // length
    frame.writeByte(Http2.TYPE_PING)
    frame.writeByte(Http2.FLAG_ACK)
    frame.writeInt(0) // connection-level
    frame.writeInt(expectedPayload1)
    frame.writeInt(expectedPayload2)

    // Check writer sends the same bytes.

 * attempting to add new elements onto the queue and it is full. This queue orders elements FIFO
 * (first-in-first-out). This data structure is logically equivalent to a circular buffer (i.e.,
 * cyclic buffer or ring buffer).
 *
 * <p>An evicting queue must be configured with a maximum size. Each time an element is added to a
 * full queue, the queue automatically removes its head element. This is different from conventional

  internal const val OPCODE_CONTINUATION = 0x0
  internal const val OPCODE_TEXT = 0x1
  internal const val OPCODE_BINARY = 0x2

  internal const val OPCODE_CONTROL_CLOSE = 0x8
  internal const val OPCODE_CONTROL_PING = 0x9
  internal const val OPCODE_CONTROL_PONG = 0xa

  /**
   * Maximum length of frame payload. Larger payloads, if supported by the frame type, can use the
   * special values [PAYLOAD_SHORT] or [PAYLOAD_LONG].
   */

    when pooled connections are evicted).

    If you have a configured ping interval, you should confirm that it is long
    enough for a roundtrip from client to server. If your ping interval is too
    short, slow connections may be misinterpreted as failed connections. A ping
    interval of 30 seconds is reasonable for most use cases.

#### Do-stuff-later pool

Sometimes there's an action required like calling the application layer or responding to a ping, and the thread discovering the action is not the thread that should do the work. We enqueue a runnable on this executor and it gets handled by one of the executor's threads.

### Locks

    writer.write("Hi");
    writer.close();

    assertThrows(IOException.class, () -> writer.write(" Greg"));

    assertThrows(IOException.class, () -> writer.flush());

    // close()ing already closed writer is allowed
    writer.close();
  }

   * {@code Ping-From}</a> header field name.
   *
   * @since 19.0
   */
  public static final String PING_FROM = "Ping-From";
  /**
   * The HTTP <a href="http://html.spec.whatwg.org/multipage/semantics.html#hyperlink-auditing">
   * {@code Ping-To}</a> header field name.
   *
   * @since 19.0
   */
  public static final String PING_TO = "Ping-To";

  /**
   * The HTTP <a

	biggerBufMin = 32 << 10

	// This is the maximum size of bigger buffers.
	biggerBufMax = maxBufferSize

	// If there is a queue, merge up to this many messages.
	maxMergeMessages = 30

	// clientPingInterval will ping the remote handler every 15 seconds.
	// Clients disconnect when we exceed 2 intervals.
	clientPingInterval = 15 * time.Second

	// Deadline for single (non-streaming) requests to complete.

    writer.write("Hi");
    writer.close();

    assertThrows(IOException.class, () -> writer.write(" Greg"));

    assertThrows(IOException.class, () -> writer.flush());

    // close()ing already closed writer is allowed
    writer.close();
  }

    )
    val openAtNanos = System.nanoTime()
    newWebSocket()
    clientListener.assertOpen()
    clientListener.assertFailure(
      SocketTimeoutException::class.java,
      "sent ping but didn't receive pong within 500ms (after 0 successful ping/pongs)",
    )
    latch.countDown()
    val elapsedUntilFailure = System.nanoTime() - openAtNanos
    assertThat(TimeUnit.NANOSECONDS.toMillis(elapsedUntilFailure).toDouble())