* used so that OkHttp can learn from its mistakes: if there was a failure attempting to connect to
 * a specific IP address or proxy server, that failure is remembered and alternate routes are
 * preferred.
 */
class RouteDatabase {
  private val _failedRoutes = mutableSetOf<Route>()

  val failedRoutes: Set<Route>
    @Synchronized get() = _failedRoutes.toSet()

  /** Records a failure connecting to [failedRoute]. */

    socketReadTimeoutMillis: Int = 10_000,
    pingIntervalMillis: Int = 10_000,
    retryOnConnectionFailure: Boolean = true,
    fastFallback: Boolean = true,
    routeDatabase: RouteDatabase = RouteDatabase(),
  ) : this(
    RealConnectionPool(
      taskRunner = taskRunner,
      maxIdleConnections = maxIdleConnections,
      keepAliveDuration = keepAliveDuration,
      timeUnit = timeUnit,

            socketReadTimeoutMillis = 10_000,
            pingIntervalMillis = 10_000,
            retryOnConnectionFailure = false,
            fastFallback = true,
            address = address,
            routeDatabase = RouteDatabase(),
            connectionUser = user,
          ),
          taskRunner,
        )
      },
    )
  }

 * IP address, and TLS mode. Connections may also be recycled.
 */
class RouteSelector(
  private val address: Address,
  private val routeDatabase: RouteDatabase,
  private val connectionUser: ConnectionUser,
  private val fastFallback: Boolean,
) {
  // State for negotiating the next proxy to use.
  private var proxies = emptyList<Proxy>()

  }

  override fun removePlanToCancel(connectPlan: ConnectPlan) {
    call.plansToCancel -= connectPlan
  }

  override fun updateRouteDatabaseAfterSuccess(route: Route) {
    call.client.routeDatabase.connected(route)
  }

  override fun connectStart(route: Route) {
    eventListener.connectStart(call, route.socketAddress, route.proxy)
    poolConnectionListener.connectStart(route, call)
  }