settings: Settings,
    )

    /** HTTP/2 only. */
    fun ackSettings()

    /**
     * Read a connection-level ping from the peer. `ack` indicates this is a reply. The data
     * in `payload1` and `payload2` opaque binary, and there are no rules on the content.
     */
    fun ping(
      ack: Boolean,
      payload1: Int,
      payload2: Int,
    )

    /**

    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))

    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.

   * {@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

      errorCode: ErrorCode,
    ) {
      check(type == -1)
      this.type = Http2.TYPE_RST_STREAM
      this.streamId = streamId
      this.errorCode = errorCode
    }

    override fun ping(
      ack: Boolean,
      payload1: Int,
      payload2: Int,
    ) {
      check(type == -1)
      type = Http2.TYPE_PING
      this.ack = ack
      this.payload1 = payload1

#### 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

    assertThat(sendPingFrame(true, expectedPayload1, expectedPayload2)).isEqualTo(frame)
    reader.nextFrame(
      requireSettings = false,
      object : BaseTestHandler() {
        override fun ping(
          ack: Boolean,
          payload1: Int,
          payload2: Int,
        ) {
          assertThat(ack).isTrue()
          assertThat(payload1).isEqualTo(expectedPayload1)

          
  /health:
    get:
      tags:
        - monitor
      summary: Check a server status
      description: Returns status
      operationId: ping
      responses:
        '200':
          description: Successful operation
          content:
            application/json:
              schema:
                type: object
                properties:

    the request already contains an `Accept` header.

 *  Fix: Don't crash with a `NullPointerException` if a server sends a close while we're sending a
    ping. OkHttp had a race condition bug.


## Version 4.6.0

_2020-04-28_

 *  Fix: Follow HTTP 307 and 308 redirects on methods other than GET and POST. We're reluctant to

        });

    }

    /**
     * Pings the search engine cluster to check connectivity and health.
     *
     * @return the ping response with cluster information
     * @throws SearchEngineClientException if the ping fails
     */
    public PingResponse ping() {
        try {
            final ClusterHealthResponse response =