*
     * The default value of 0 disables client-initiated pings.
     */
    fun pingInterval(
      interval: Long,
      unit: TimeUnit,
    ) = apply {
      pingInterval = checkDuration("interval", interval, unit)
    }

    /**
     * Sets the interval between HTTP/2 and web socket pings initiated by this client. Use this to

    pings, but it did not track whether the reply pongs were received. With this
    update OkHttp requires that every ping receive a response: if it does not
    the connection will be closed and the listener's `onFailure()` method will
    be called.

    Web sockets have always been had pings, but pings on HTTP/2 connections is
    new in this release. Pings are used for connections that are busy carrying

        .pingInterval(Duration.ofMillis(500))
        .build()

    // Set up the server to ignore the socket. It won't respond to pings!
    server.enqueue(MockResponse(socketPolicy = StallSocketAtStart))

    // Make a call. It'll fail as soon as our pings detect a problem.
    val call = client.newCall(Request(server.url("/")))
    val executeAtNanos = System.nanoTime()