/** 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)
  }

  /**

![Events Diagram](../assets/images/events@2x.png)

Here’s a [sample event listener](https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/PrintEventsNonConcurrent.java) that prints each event with a timestamp.

```java

    Buffer result = new Buffer();
    result.writeAll(Okio.source(file));
    return result;
  }

  private String contentType(String path) {
    if (path.endsWith(".png")) return "image/png";
    if (path.endsWith(".jpg")) return "image/jpeg";
    if (path.endsWith(".jpeg")) return "image/jpeg";
    if (path.endsWith(".gif")) return "image/gif";

  }

  @Test
  fun flagOverlapOn0x1() {
    assertThat(frameLog(true, 0, 0, TYPE_SETTINGS, 0x1))
      .isEqualTo("<< 0x00000000     0 SETTINGS      ACK")
    assertThat(frameLog(true, 0, 8, TYPE_PING, 0x1))
      .isEqualTo("<< 0x00000000     8 PING          ACK")
    assertThat(frameLog(true, 3, 0, TYPE_HEADERS, 0x1))
      .isEqualTo("<< 0x00000003     0 HEADERS       END_STREAM")
    assertThat(frameLog(true, 3, 0, TYPE_DATA, 0x1))

    fail("")
  }

  override fun settings(
    clearPrevious: Boolean,
    settings: Settings,
  ) {
    fail("")
  }

  override fun ackSettings() {
    fail("")
  }

  override fun ping(
    ack: Boolean,
    payload1: Int,
    payload2: Int,
  ) {
    fail("")
  }

  override fun goAway(
    lastGoodStreamId: Int,
    errorCode: ErrorCode,
    debugData: ByteString,
  ) {

    }
  }

  @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.

     */
    fun add(
      pattern: String,
      vararg pins: String,
    ) = apply {
      for (pin in pins) {
        this.pins.add(Pin(pattern, pin))
      }
    }

    fun build(): CertificatePinner = CertificatePinner(pins.toSet())
  }

  companion object {
    @JvmField
    val DEFAULT = Builder().build()

    @JvmStatic

    assertFalse(pin.matchesHostname("www.example.com"))
  }

  @Test fun testMatchesSha256() {
    val pin = Pin("example.com", certA1Sha256Pin)
    assertTrue(pin.matchesCertificate(certA1.certificate))
    assertFalse(pin.matchesCertificate(certB1.certificate))
  }

  @Test fun testMatchesSha1() {
    val pin = Pin("example.com", certC1Sha1Pin)
    assertTrue(pin.matchesCertificate(certC1.certificate))

Lokhttp3/internal/http2/Http2Connection$ReaderRunnable$applyAndAckSettings$1$1$2;
Lokhttp3/internal/http2/Http2Connection$ReaderRunnable$headers$1$1;
Lokhttp3/internal/http2/Http2Connection$ReaderRunnable$ping$2;
Lokhttp3/internal/http2/Http2Connection$ReaderRunnable$settings$1;
Lokhttp3/internal/http2/Http2Connection$ReaderRunnable;
Lokhttp3/internal/http2/Http2Connection$pushDataLater$1;

events_with_failures@2x.png...