val commonEmptyHeaders: Headers = Headers.headersOf()
val commonEmptyRequestBody: RequestBody = EMPTY_BYTE_ARRAY.toRequestBody()
val commonEmptyResponse: ResponseBody = EMPTY_BYTE_ARRAY.toResponseBody()

internal fun <T> interleave(
  a: Iterable<T>,
  b: Iterable<T>,
): List<T> {
  val ia = a.iterator()
  val ib = b.iterator()

  return buildList {
    while (ia.hasNext() || ib.hasNext()) {
      if (ia.hasNext()) {

 *
 * This nesting is typical but not strict. For example, when calls use "Expect: continue" the
 * request body start and end events occur within the response header events. Similarly,
 * [duplex calls][RequestBody.isDuplex] interleave the request and response bodies.
 *
 * Since connections may be reused, the proxy selection, DNS, and connect events may not be present
 * for a call. In future releases of OkHttp these events may also occur concurrently to permit

      if (result == CancellationException.class) {
        assertTrue(future.isCancelled());
        assertTrue(cancellationSuccess.get());
        // cancellation can interleave in 3 ways
        // 1. prior to setFuture
        // 2. after setFuture before set() on the future assigned
        // 3. after setFuture and set() are called but before the listener completes.

   *  * If it is a message frame this will result in a single call to [FrameCallback.onReadMessage].
   *    If the message spans multiple frames, each interleaved control frame will result in a
   *    corresponding call to [FrameCallback].
   */
  @Throws(IOException::class)
  fun processNextFrame() {
    readHeader()
    if (isControlFrame) {
      readControlFrame()

  /**
   * Each instance of MinMaxPriorityQueue encapsulates two instances of Heap: a min-heap and a
   * max-heap. Conceptually, these might each have their own array for storage, but for efficiency's
   * sake they are stored interleaved on alternate heap levels in the same array (MMPQ.queue).
   */
  @WeakOuter
  class Heap {
    final Ordering<E> ordering;

    @SuppressWarnings("nullness:initialization.field.uninitialized")
    @Weak

   * We always do timeouts in the HTTP server role. For clients, we only do timeouts after the
   * request is transmitted. This is only interesting for duplex calls where the request and
   * response may be interleaved.
   *
   * Read this value only once for each enter/exit pair because its value can change.
   */
  private fun doReadTimeout() = !connection.client || sink.closed || sink.finished

  /**

  /**
   * Each instance of MinMaxPriorityQueue encapsulates two instances of Heap: a min-heap and a
   * max-heap. Conceptually, these might each have their own array for storage, but for efficiency's
   * sake they are stored interleaved on alternate heap levels in the same array (MMPQ.queue).
   */
  @WeakOuter
  class Heap {
    final Ordering<E> ordering;

    @SuppressWarnings("nullness:initialization.field.uninitialized")
    @Weak