val connection = this.connection!!
    connection.lock.assertHeld()

    val calls = connection.calls
    val index = calls.indexOfFirst { it.get() == this@RealCall }
    check(index != -1)

    calls.removeAt(index)
    this.connection = null

    if (calls.isEmpty()) {
      connection.idleAtNs = System.nanoTime()
      if (connectionPool.connectionBecameIdle(connection)) {

   * `allocations.size() < allocationLimit` then new streams can be created on this connection.
   */
  internal var allocationLimit = 1
    private set

  /** Current calls carried by this connection. */
  val calls = mutableListOf<Reference<RealCall>>()

  /** Timestamp when `allocations.size()` reached zero. Also assigned upon initial connection. */
  var idleAtNs = Long.MAX_VALUE

  /**

    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
    calls that use a pooled connection.


## Version 4.3.1

_2020-01-07_

 *  Fix: Don't crash with a `NullPointerException` when a web socket is closed before it connects.

  ) {
    delegate.setPolicy(address, policy)
  }

  /**
   * A policy for how the pool should treat a specific address.
   */
  class AddressPolicy(
    /**
     * How many concurrent calls should be possible to make at any time.
     * The pool will routinely try to pre-emptively open connections to satisfy this minimum.
     * Connections will still be closed if they idle beyond the keep-alive but will be replaced.

    executeSynchronously(request).assertFailure("$dns returned no addresses for android.com")
    dns.assertRequests("android.com")
  }

  /** We had a bug where failed HTTP/2 calls could break the entire connection.  */
  @Flaky
  @Test
  fun failingCallsDoNotInterfereWithConnection() {
    enableProtocol(Protocol.HTTP_2)
    server.enqueue(MockResponse(body = "Response 1"))

    // Cancel some calls. That doesn't impact running or queued.
    a2.cancel()
    a3.cancel()
    assertThat(dispatcher.runningCalls())
      .containsExactlyInAnyOrder(a1, a2)
    assertThat(dispatcher.queuedCalls()).isEmpty()

    // Let the calls finish.
    waiting.countDown()
    t1.join()
    t2.join()

    // Now we should have 0 running calls and 0 queued calls.

  /**
   * True if this task faker has ever had multiple tasks scheduled to run concurrently. Guarded by
   * [TaskRunner.lock].
   */
  var isParallel = false

  /** Number of calls to [TaskRunner.Backend.execute]. Guarded by [TaskRunner.lock]. */
  var executeCallCount = 0

  /** Guarded by [taskRunner]. */
  var nanoTime = 0L
    private set

    val c1 = factory.newConnection(pool, routeA1, 0L)
    allocateAndLeakAllocation(poolApi, c1)
    awaitGarbageCollection()
    assertThat(pool.closeConnections(100L)).isEqualTo(0L)
    assertThat(c1.calls).isEmpty()

    // Can't allocate once a leak has been detected.
    assertThat(c1.noNewExchanges).isTrue()
  }

  @Test fun interruptStopsThread() {
    val realTaskRunner = TaskRunner.INSTANCE

    val call2 = client.newCall(Request(server.url("/")))
    call2.execute().use { response ->
      assertThat(
        response.body.string(),
      ).isEqualTo("b")
    }

    // Calls succeed after the degraded pong timeout because the degraded pong was received.
    Thread.sleep(TimeUnit.NANOSECONDS.toMillis(Http2Connection.DEGRADED_PONG_TIMEOUT_NS.toLong()))

        return executorServiceOrNull!!
      }

  /** Ready async calls in the order they'll be run. */
  private val readyAsyncCalls = ArrayDeque<AsyncCall>()

  /** Running asynchronous calls. Includes canceled calls that haven't finished yet. */
  private val runningAsyncCalls = ArrayDeque<AsyncCall>()

  /** Running synchronous calls. Includes canceled calls that haven't finished yet. */