### Locks

We have 3 different things that we synchronize on.

#### Http2Connection

This lock guards internal state of each connection. This lock is never held for blocking operations. That means that we acquire the lock, read or write a few fields and release the lock. No I/O and no application-layer callbacks.

#### Http2Stream

   * be removed from the execution schedule.
   */
  fun cancelAll() {
    lock.assertNotHeld()

    taskRunner.lock.withLock {
      if (cancelAllAndDecide()) {
        taskRunner.kickCoordinator(this)
      }
    }
  }

  fun shutdown() {
    lock.assertNotHeld()

    taskRunner.lock.withLock {
      shutdown = true
      if (cancelAllAndDecide()) {

Yuri Schimke <******@****.***> 1690028931 +0100

  internal inline fun Any.assertThreadHoldsLock() {
    if (assertionsEnabled && !taskRunner.lock.isHeldByCurrentThread) {
      throw AssertionError("Thread ${Thread.currentThread().name} MUST hold lock on $this")
    }
  }

  @Suppress("NOTHING_TO_INLINE")
  internal inline fun Any.assertThreadDoesntHoldLock() {
    if (assertionsEnabled && taskRunner.lock.isHeldByCurrentThread) {

 */
class TaskRunner(
  val backend: Backend,
  internal val logger: Logger = TaskRunner.logger,
) {
  val lock: ReentrantLock = ReentrantLock()
  val condition: Condition = lock.newCondition()

  private var nextQueueName = 10000
  private var coordinatorWaiting = false
  private var coordinatorWakeUpAt = 0L

  /**

    throw AssertionError("Thread ${Thread.currentThread().name} MUST hold lock on $this")
  }
}

@Suppress("NOTHING_TO_INLINE")
internal inline fun Any.assertThreadHoldsLock() {
  if (assertionsEnabled && !Thread.holdsLock(this)) {
    throw AssertionError("Thread ${Thread.currentThread().name} MUST hold lock on $this")
  }
}

@Suppress("NOTHING_TO_INLINE")

import okio.BufferedSink

/** Writes HTTP/2 transport frames. */
@Suppress("NAME_SHADOWING")
class Http2Writer(
  private val sink: BufferedSink,
  private val client: Boolean,
) : Closeable {
  internal val lock: ReentrantLock = ReentrantLock()

  private val hpackBuffer: Buffer = Buffer()
  private var maxFrameSize: Int = INITIAL_MAX_FRAME_SIZE
  private var closed: Boolean = false

    fail the call.

 *  Fix: Recover gracefully when a coalesced connection immediately goes unhealthy.

## Version 3.14.2

_2019-05-19_

 *  Fix: Lock in a route when recovering from an HTTP/2 connection error. We had a bug where two
    calls that failed at the same time could cause OkHttp to crash with a `NoSuchElementException`
    instead of the expected `IOException`.

  /** The timestamp of the last taken event, used to measure elapsed time between events. */
  private var lastTimestampNs: Long? = null

  /** Confirm that the thread does not hold a lock on `lock` during the callback. */
  fun forbidLock(lock: Any) {
    forbiddenLocks.add(lock)
  }

  /**
   * Removes recorded events up to (and including) an event is found whose class equals [eventClass]
   * and returns it.
   */

in OkHttp 3.x and are final in 4.x. These were made non-final for use with mocking frameworks like
[Mockito][mockito]. We believe subtyping `OkHttpClient` is the wrong way to test with OkHttp. If
you must, mock `Call.Factory` which is the interface that `OkHttpClient` implements.

#### Internal API changes

The `okhttp3.internal` package is not a published API and we change it frequently without warning.