) {
    lock.withLock {
      val oldLimit = allocationLimit
      allocationLimit = settings.getMaxConcurrentStreams()

      if (allocationLimit < oldLimit) {
        // We might need new connections to keep policies satisfied
        connectionPool.scheduleOpener(route.address)
      } else if (allocationLimit > oldLimit) {
        // We might no longer need some connections
        connectionPool.scheduleCloser()
      }

    useful for splitting out canceled calls in metrics.

 *  New: Publish a [bill of materials (BOM)][bom] for OkHttp. Depend on this from Gradle or Maven to
    keep all of your OkHttp artifacts on the same version, even if they're declared via transitive
    dependencies. You can even omit versions when declaring other OkHttp dependencies.

    ```kotlin
    dependencies {

      .assertLogEqual("<-- END HTTP")
      .assertNoMoreLogs()
    networkLogs
      .assertLogEqual("--> GET $url http/1.1")
      .assertLogEqual("Host: $host")
      .assertLogEqual("Connection: Keep-Alive")
      .assertLogEqual("Accept-Encoding: gzip")
      .assertLogMatch(Regex("""User-Agent: okhttp/.+"""))
      .assertLogEqual("--> END GET")
      .assertLogMatch(Regex("""<-- 200 OK $url \(\d+ms\)"""))

    assertThat(request.requestLine).isEqualTo(
      "GET /a/deep/path?key=foo%20bar HTTP/1.1",
    )
    val requestUrl = request.requestUrl
    assertThat(requestUrl!!.scheme).isEqualTo("http")
    assertThat(requestUrl.host).isEqualTo(server.hostName)
    assertThat(requestUrl.port).isEqualTo(server.port)
    assertThat(requestUrl.encodedPath).isEqualTo("/a/deep/path")

        when (val label = match.groups[1]!!.value) {
          "CERTIFICATE" -> {
            require(certificatePem == null) { "string includes multiple certificates" }
            certificatePem = match.groups[0]!!.value // Keep --BEGIN-- and --END-- for certificates.
          }
          "PRIVATE KEY" -> {
            require(pkcs8Base64 == null) { "string includes multiple private keys" }

     * 13.5.1.
     */
    private fun isEndToEnd(fieldName: String): Boolean {
      return !"Connection".equals(fieldName, ignoreCase = true) &&
        !"Keep-Alive".equals(fieldName, ignoreCase = true) &&
        !"Proxy-Authenticate".equals(fieldName, ignoreCase = true) &&
        !"Proxy-Authorization".equals(fieldName, ignoreCase = true) &&

        taskRunner.condition.await()
      }
    } finally {
      serialTaskQueue.remove(yieldCompleteTask)
    }

    // If we're yielding until we're exhausted and a task run, keep going until a task doesn't run.
    if (strategy == ResumePriority.AfterOtherTasks && otherTasksStarted) {
      return yieldUntil(strategy, condition)
    }
  }

  private enum class ResumePriority {

      Request.Builder()
        .url(route.address.url)
        .method("CONNECT", null)
        .header("Host", route.address.url.toHostHeader(includeDefaultPort = true))
        .header("Proxy-Connection", "Keep-Alive") // For HTTP/1.0 proxies like Squid.
        .header("User-Agent", USER_AGENT)
        .build()

    val fakeAuthChallengeResponse =
      Response.Builder()
        .request(proxyConnectRequest)

    mockResponse = mockResponse.setChunkedBody(Buffer(), 0)
    mockResponse = mockResponse.setChunkedBody("", 0)
    var socketPolicy: SocketPolicy = mockResponse.socketPolicy
    mockResponse.socketPolicy = SocketPolicy.KEEP_OPEN
    var http2ErrorCode: Int = mockResponse.http2ErrorCode
    mockResponse.http2ErrorCode = 0
    mockResponse = mockResponse.throttleBody(0L, 0L, TimeUnit.SECONDS)

   * simultaneously adopted and removed.
   */
  private val connections = ConcurrentLinkedQueue<RealConnection>()

  init {
    // Put a floor on the keep alive duration, otherwise cleanup will spin loop.
    require(keepAliveDuration > 0L) { "keepAliveDuration <= 0: $keepAliveDuration" }
  }

  fun idleConnectionCount(): Int {
    return connections.count {