* share the same [Address] may share a [Connection]. This class implements the policy
 * of which connections to keep open for future use.
 *
 * @constructor Create a new connection pool with tuning parameters appropriate for a single-user
 * application. The tuning parameters in this pool are subject to change in future OkHttp releases.
 * Currently this pool holds up to 5 idle connections which will be evicted after 5 minutes of
 * inactivity.
 */

![Events Diagram](../assets/images/******@****.***)

### Availability

      )
    }

    client.routeDatabase.failed(failedRoute)
  }

  /**
   * Track a failure using this connection. This may prevent both the connection and its route from
   * being used for future exchanges.
   */
  override fun trackFailure(
    call: RealCall,
    e: IOException?,
  ) {
    var noNewExchangesEvent = false
    lock.withLock {
      if (e is StreamResetException) {

import java.net.InetSocketAddress
import java.net.ServerSocket
import java.security.PrivateKey
import java.util.concurrent.ExecutorService
import java.util.concurrent.Executors
import java.util.concurrent.Future
import javax.net.ServerSocketFactory
import javax.net.SocketFactory
import javax.net.ssl.SSLSocket
import okhttp3.Handshake
import okhttp3.Handshake.Companion.handshake
import okhttp3.TestUtil.threadFactory

   * currently-executing task unless it is also scheduled for future execution.
   */
  val scheduledTasks: List<Task>
    get() = taskRunner.lock.withLock { futureTasks.toList() }

  /**
   * Schedules [task] for execution in [delayNanos]. A task may only have one future execution
   * scheduled. If the task is already in the queue, the earliest execution time is used.
   *

   * @throws IllegalStateException when the call has already been executed.
   */
  @Throws(IOException::class)
  fun execute(): Response

  /**
   * Schedules the request to be executed at some point in the future.
   *
   * The [dispatcher][OkHttpClient.dispatcher] defines when the request will run: usually
   * immediately unless there are several other requests currently being executed.
   *

    return client.newCall(request).execute()
  }

  /**
   * @param delta the offset from the current date to use. Negative values yield dates in the past;
   *     positive values yield dates in the future.
   */
  private fun formatDate(
    delta: Long,
    timeUnit: TimeUnit,
  ): String? {
    return formatDate(Date(System.currentTimeMillis() + timeUnit.toMillis(delta)))
  }

Once the response has been received, the connection will be returned to the pool so it can be reused for a future request. Connections are evicted from the pool after a period of inactivity.

### [Fast Fallback](https://square.github.io/okhttp/4.x/okhttp/okhttp3/-ok-http-client/-builder/fast-fallback/)

 * connections should expect repetition of stream IDs.
 *
 * Return true to request cancellation of a pushed stream.  Note that this does not guarantee
 * future frames won't arrive on the stream ID.
 */
interface PushObserver {
  /**
   * Describes the request that the server intends to push a response for.
   *
   * @param streamId server-initiated stream ID: an even number.

     * security. ECDSA keys are noticeably faster than RSA keys.
     *
     * This is the default configuration and has been since this API was introduced in OkHttp
     * 3.11.0. Note that the default may change in future releases.
     */
    fun ecdsa256() =
      apply {
        keyAlgorithm = "EC"
        keySize = 256
      }

    /**