/**
   * Waits for the {@link ServiceManager} to become {@linkplain #isHealthy() healthy}. The manager
   * will become healthy after all the component services have reached the {@linkplain State#RUNNING
   * running} state.
   *
   * @throws IllegalStateException if the service manager reaches a state from which it cannot
   *     become {@linkplain #isHealthy() healthy}.
   */
  public void awaitHealthy() {
    state.awaitHealthy();

    manager.addListener(listener, directExecutor());
    assertState(manager, Service.State.NEW, a, b);
    assertFalse(manager.isHealthy());
    manager.startAsync().awaitHealthy();
    assertState(manager, Service.State.RUNNING, a, b);
    assertTrue(manager.isHealthy());
    assertTrue(listener.healthyCalled);
    assertFalse(listener.stoppedCalled);
    assertTrue(listener.failedServices.isEmpty());

    manager.addListener(listener, directExecutor());
    assertState(manager, Service.State.NEW, a, b);
    assertFalse(manager.isHealthy());
    manager.startAsync().awaitHealthy();
    assertState(manager, Service.State.RUNNING, a, b);
    assertTrue(manager.isHealthy());
    assertTrue(listener.healthyCalled);
    assertFalse(listener.stoppedCalled);
    assertTrue(listener.failedServices.isEmpty());

  private fun waitForConnectionShutdown(connection: RealConnection?) {
    if (connection!!.isHealthy(false)) {
      Thread.sleep(100L)
    }
    if (connection.isHealthy(false)) {
      Thread.sleep(2000L)
    }
    if (connection.isHealthy(false)) {
      throw TimeoutException("connection didn't shutdown within timeout")
    }
  }

  /**

      withLock {
        if (isShutdown) {
          throw ConnectionShutdownException()
        }
        okHttpSettings.merge(settings)
      }
      writer.settings(settings)
    }
  }

  fun isHealthy(nowNs: Long): Boolean {
    withLock {
      if (isShutdown) return false

      // A degraded pong is overdue.
      if (degradedPongsReceived < degradedPingsSent && nowNs >= degradedPongDeadlineNs) return false

    val candidate = call.connection ?: return null

    // Make sure this connection is healthy & eligible for new exchanges. If it's no longer needed
    // then we're on the hook to close it.
    val healthy = candidate.isHealthy(doExtensiveHealthChecks)
    var noNewExchangesEvent = false
    val toClose: Socket? =
      candidate.withLock {
        when {
          !healthy -> {
            noNewExchangesEvent = !candidate.noNewExchanges

 * attempting to read with a short timeout. If the fails immediately we know the socket is
 * unhealthy.
 *
 * @param source the source used to read bytes from the socket.
 */
internal fun Socket.isHealthy(source: BufferedSource): Boolean =
  try {
    val readTimeout = soTimeout
    try {
      soTimeout = 1
      !source.exhausted()
    } finally {
      soTimeout = readTimeout
    }

              true
            }
          }
        }
      if (!acquired) continue

      // Confirm the connection is healthy and return it.
      if (connection.isHealthy(doExtensiveHealthChecks)) return connection

      // In the second synchronized block, release the unhealthy acquired connection. We're also on
      // the hook to close this connection if it's no longer in use.