importResults.writeOut(sink)
      }
    }

  /**
   * These assertions ensure the [PublicSuffixDatabase] remains correct. The specification is
   * very flexible regarding wildcard rules, but this flexibility is not something currently used
   * in practice. To simplify the implementation, we've avoided implementing the flexible rules in

    Castle is great! But it's a large dependency (6.5 MiB) and its security provider feature
    impacts VM-wide behavior.

 *  New: Reduce contention for applications that make a very high number of concurrent requests.
    Previously OkHttp used its connection pool as a lock when making changes to connections and
    calls. With this change each connection is locked independently.

   * callback has returned. Synchronous calls become idle once [execute()][Call.execute] returns.
   * This means that if you are doing synchronous calls the network layer will not truly be idle
   * until every returned [Response] has been closed.
   */
  var idleCallback: Runnable? = null
    get() = this.withLock { field }
    set(value) {
      this.withLock { field = value }
    }

  @ParameterizedTest
  @ArgumentsSource(ProtocolParamProvider::class)
  fun pingsTransmitted(
    protocol: Protocol,
    mockWebServer: MockWebServer,
  ) {
    setUp(protocol, mockWebServer)
    // Ping every 500 ms, starting at 500 ms.
    client =
      client.newBuilder()
        .pingInterval(Duration.ofMillis(500))
        .build()

    // Delay the response to give 1 ping enough time to be sent and replied to.

    Settings().apply {
      // Flow control was designed more for servers, or proxies than edge clients. If we are a client,
      // set the flow control window to 16MiB.  This avoids thrashing window updates every 64KiB, yet
      // small enough to avoid blowing up the heap.
      if (builder.client) {
        set(Settings.INITIAL_WINDOW_SIZE, OKHTTP_CLIENT_WINDOW_SIZE)
      }
    }

  /**

 *  Fix: `OkHttpClient` no longer implements `Cloneable`. It never should have; the class is
    immutable. This is left over from OkHttp 2.x (!) when that class was mutable. We're using the
    5.x upgrade as an opportunity to remove very obsolete APIs.
 *  Fix: Recover gracefully when Android's `NativeCrypto` crashes with `"ssl == null"`. This occurs
    when OkHttp retrieves ALPN state on a closed connection.
 *  Upgrade: [Kotlin 1.6.21][kotlin_1_6_21].