internal fun connectFailed(
    client: OkHttpClient,
    failedRoute: Route,
    failure: IOException,
  ) {
    // Tell the proxy selector when we fail to connect on a fresh connection.
    if (failedRoute.proxy.type() != Proxy.Type.DIRECT) {
      val address = failedRoute.address
      address.proxySelector.connectFailed(
        address.url.toUri(),

 *  New: Build with Kotlin 1.3.41, BouncyCastle 1.62, and Conscrypt 2.2.1.
 *  Fix: Recover gracefully when a coalesced connection immediately goes unhealthy.
 *  Fix: Defer the `SecurityException` when looking up the default proxy selector.
 *  Fix: Don't use brackets formatting IPv6 host names in MockWebServer.
 *  Fix: Don't permit cache iterators to remove entries that are being written.


## Version 4.0.1

_2019-07-10_

    assertThat(selection.hasNext()).isFalse()
    assertThat(routeSelector.hasNext()).isFalse()
    dns.assertRequests(uriHost)
    proxySelector.assertRequests() // No proxy selector requests!
  }

  /**
   * Don't call through to the proxy selector if we don't have a host name.
   * https://github.com/square/okhttp/issues/5770
   */
  @Test fun proxySelectorNotCalledForNullHost() {

 */
package okhttp3.internal.proxy

import java.io.IOException
import java.net.Proxy
import java.net.ProxySelector
import java.net.SocketAddress
import java.net.URI

/**
 * A proxy selector that always returns the [Proxy.NO_PROXY].
 */
object NullProxySelector : ProxySelector() {
  override fun select(uri: URI?): List<Proxy> {
    requireNotNull(uri) { "uri must not be null" }
    return listOf(Proxy.NO_PROXY)

    executeSynchronously("/")
      .assertFailure(IOException::class.java)
  }

  @Test
  fun requestBodySurvivesRetries() {
    server.enqueue(MockResponse())

    // Enable a misconfigured proxy selector to guarantee that the request is retried.
    client =
      client.newBuilder()
        .proxySelector(
          FakeProxySelector()
            .addProxy(server2.toProxyAddress())

 * connection the client has many options:
 *
 *  * **HTTP proxy:** a proxy server may be explicitly configured for the client. Otherwise, the
 *    [proxy selector][java.net.ProxySelector] is used. It may return multiple proxies to attempt.
 *  * **IP address:** whether connecting directly to an origin server or a proxy, opening a socket

    return delegate!!.handshakeApplicationProtocol
  }

  override fun setHandshakeApplicationProtocolSelector(selector: BiFunction<SSLSocket, MutableList<String>, String>?) {
    delegate!!.handshakeApplicationProtocolSelector = selector
  }

  override fun getHandshakeApplicationProtocolSelector(): BiFunction<SSLSocket, MutableList<String>, String> {

    // If we have a routes left, use 'em.
    if (routeSelection?.hasNext() == true) return true

    // If we haven't initialized the route selector yet, assume it'll have at least one route.
    val localRouteSelector = routeSelector ?: return true

    // If we do have a route selector, use its routes.
    return localRouteSelector.hasNext()
  }

  /**

    if (!isRecoverable(e, requestSendStarted)) return false

    // No more routes to attempt.
    if (!call.retryAfterFailure()) return false

    // For failure recovery, use the same route selector with a new connection.
    return true
  }

  private fun requestIsOneShot(
    e: IOException,
    userRequest: Request,
  ): Boolean {
    val requestBody = userRequest.body

     * Sets the proxy selection policy to be used if no [proxy][proxy] is specified explicitly. The
     * proxy selector may return multiple proxies; in that case they will be tried in sequence until
     * a successful connection is established.
     *
     * If unset, the [system-wide default][ProxySelector.getDefault] proxy selector will be used.
     */
    fun proxySelector(proxySelector: ProxySelector) =
      apply {