http2Connection.start()
  }

  /**
   * Returns true if this connection can carry a stream allocation to `address`. If non-null
   * `route` is the resolved route for a connection.
   */
  internal fun isEligible(
    address: Address,
    routes: List<Route>?,
  ): Boolean {
    lock.assertHeld()

    // If this connection is not accepting new exchanges, we're done.

    automatically retry on an unshared connection.
 *  Fix: Don't crash if a TLS tunnel's response body is truncated.
 *  Fix: Don't track unusable routes beyond their usefulness. We had a bug where we could track
    certain bad routes indefinitely; now we only track the ones that could be necessary.
 *  Fix: Defer proxy selection until a proxy is required. This saves calls to `ProxySelector` on

import okhttp3.Response
import okhttp3.Route

class RecordingOkAuthenticator(
  val credential: String?,
  val scheme: String?,
) : Authenticator {
  val responses = mutableListOf<Response>()
  val routes = mutableListOf<Route>()

  fun onlyResponse() = responses.single()

  fun onlyRoute() = routes.single()

  @Throws(IOException::class)
  override fun authenticate(
    route: Route?,
    response: Response,

  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>?,

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3.internal.connection

import java.io.IOException

/** Attempt routes one at a time until one connects. */
internal class SequentialExchangeFinder(
  override val routePlanner: RoutePlanner,
) : ExchangeFinder {
  override fun find(): RealConnection {
    var firstException: IOException? = null

   *
   * This will be invoked only once for a single [Call]. Retries of different routes or redirects
   * will be handled within the boundaries of a single [callStart] and [callEnd]/[callFailed] pair.
   */
  open fun callStart(call: Call) {
  }

  /**
   * Invoked prior to a proxy selection.
   *
   * This will be invoked for route selection regardless of whether the client

    }
  }

  override fun connectStart(
    route: Route,
    call: Call,
  ) = logEvent(ConnectionEvent.ConnectStart(System.nanoTime(), route, call))

  override fun connectFailed(
    route: Route,
    call: Call,
    failure: IOException,
  ) = logEvent(
    ConnectionEvent.ConnectFailed(System.nanoTime(), route, call, failure),
  )

  override fun connectEnd(

import okhttp3.OkHttpClient
import okhttp3.Request
import okhttp3.Response
import okhttp3.Route

class Authenticate {
  private val client =
    OkHttpClient.Builder()
      .authenticator(
        object : Authenticator {
          @Throws(IOException::class)
          override fun authenticate(
            route: Route?,
            response: Response,
          ): Request? {

   *
   * The route is best effort, it currently may not always be provided even when logically
   * available. It may also not be provided when an authenticator is re-used manually in an
   * application interceptor, such as when implementing client-specific retries.
   */
  @Throws(IOException::class)
  fun authenticate(
    route: Route?,
    response: Response,
  ): Request?