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

  /** Records a failure connecting to [failedRoute]. */
  @Synchronized fun failed(failedRoute: Route) {
    _failedRoutes.add(failedRoute)
  }

  /** Records success connecting to [route]. */
  @Synchronized fun connected(route: Route) {
    _failedRoutes.remove(route)
  }

   *
   * If [routes] is non-null these are the resolved routes (ie. IP addresses) for the connection.
   * This is used to coalesce related domains to the same HTTP/2 connection, such as `square.com`
   * and `square.ca`.
   */
  fun callAcquirePooledConnection(
    doExtensiveHealthChecks: Boolean,
    address: Address,
    connectionUser: ConnectionUser,
    routes: List<Route>?,
    requireMultiplexed: Boolean,

  /** Returns a plan for the first attempt at [route]. This throws if no plan is possible. */
  @Throws(IOException::class)
  internal fun planConnectToRoute(
    route: Route,
    routes: List<Route>? = null,
  ): ConnectPlan {
    if (route.address.sslSocketFactory == null) {
      if (ConnectionSpec.CLEARTEXT !in route.address.connectionSpecs) {
        throw UnknownServiceException("CLEARTEXT communication not enabled for client")

  }

  private fun assertRoute(
    route: Route,
    address: Address,
    proxy: Proxy,
    socketAddress: InetAddress,
    socketPort: Int,
  ) {
    assertThat(route.address).isEqualTo(address)
    assertThat(route.proxy).isEqualTo(proxy)
    assertThat(route.socketAddress.address).isEqualTo(socketAddress)
    assertThat(route.socketAddress.port).isEqualTo(socketPort)
  }

    }
  }

  override fun protocol(): Protocol = protocol

  override fun toString(): String =
    "Connection{${route.address.url.host}:${route.address.url.port}," +
      " proxy=${route.proxy}" +
      " hostAddress=${route.socketAddress}" +
      " cipherSuite=${handshake?.cipherSuite ?: "none"}" +
      " protocol=$protocol}"

  companion object {

  }

  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)
  }

  override fun connectFailed(
    route: Route,
    protocol: Protocol?,
    e: IOException,
  ) {

  }

  override fun updateRouteDatabaseAfterSuccess(route: Route) {
  }

  override fun connectStart(route: Route) {
  }

  override fun secureConnectStart() {
  }

  override fun secureConnectEnd(handshake: Handshake?) {
  }

  override fun callConnectEnd(
    route: Route,
    protocol: Protocol?,
  ) {
  }

  override fun connectionConnectEnd(

  fun callConnectEnd(
    route: Route,
    protocol: Protocol?,
  )

  fun connectionConnectEnd(
    connection: Connection,
    route: Route,
  )

  fun connectFailed(
    route: Route,
    protocol: Protocol?,
    e: IOException,
  )

  fun connectionAcquired(connection: Connection)

  fun acquireConnectionNoEvents(connection: RealConnection)

In OkHttp some fields of the address come from the URL (scheme, hostname, port) and the rest come from the [OkHttpClient](https://square.github.io/okhttp/4.x/okhttp/okhttp3/-ok-http-client/).

### [Routes](https://square.github.io/okhttp/4.x/okhttp/okhttp3/-route/)

    override val timestampNs: Long,
    val route: Route,
    val call: Call,
  ) : ConnectionEvent()

  data class ConnectFailed(
    override val timestampNs: Long,
    val route: Route,
    val call: Call,
    val exception: IOException,
  ) : ConnectionEvent() {
    override fun closes(event: ConnectionEvent): Boolean = event is ConnectStart && call == event.call && route == event.route
  }

  data class ConnectEnd(