fun sleep(durationNanos: Long) {
    taskRunner.withLock {
      val sleepUntil = nanoTime + durationNanos
      yieldUntil { nanoTime >= sleepUntil }
    }
  }

  /**
   * Artificially stall until manually resumed by the test thread with [runTasks]. Use this to
   * simulate races in tasks that doesn't have a deterministic sequence.
   */
  fun yield() {
    taskRunner.assertLockNotHeld()

Actually, all (or most) of the web frameworks work in this same way.

You never call those functions directly. They are called by your framework (in this case, **FastAPI**).

     *     {@link #whenAllComplete(Iterable)} or {@link #whenAllComplete(Iterable)}
     * @throws IllegalStateException if called outside of a call to {@link
     *     CombiningCallable#call(DeferredCloser, Peeker)} or {@link
     *     AsyncCombiningCallable#call(DeferredCloser, Peeker)}
     */
    @ParametricNullness
    public <D extends @Nullable Object> D getDone(ClosingFuture<D> closingFuture)

All the cgo CPPFLAGS and CFLAGS directives in a package are concatenated and
used to compile C files in that package. All the CPPFLAGS and CXXFLAGS
directives in a package are concatenated and used to compile C++ files in that
package. All the CPPFLAGS and FFLAGS directives in a package are concatenated
and used to compile Fortran files in that package. All the LDFLAGS directives

    happened enough then eventually the connection would stall.

 *  Fix: Acknowledge and apply inbound HTTP/2 settings atomically. Previously we had a race where we
    could use new flow control capacity before acknowledging it, causing strict HTTP/2 servers to
    fail the call.


## Version 4.1.1

_2019-09-05_

        existingCounter = countMap.putIfAbsent(element, new AtomicInteger(occurrences));
        if (existingCounter == null) {
          return 0;
        }
        // existingCounter != null: fall through to operate against the existing AtomicInteger
      }

      while (true) {
        int oldValue = existingCounter.get();
        if (oldValue != 0) {
          try {

        existingCounter = countMap.putIfAbsent(element, new AtomicInteger(occurrences));
        if (existingCounter == null) {
          return 0;
        }
        // existingCounter != null: fall through to operate against the existing AtomicInteger
      }

      while (true) {
        int oldValue = existingCounter.get();
        if (oldValue != 0) {
          try {

    override val call: Call,
  ) : CallEvent() {
    override fun closes(event: CallEvent): Boolean = event is CallStart && call == event.call
  }

  data class CallFailed(
    override val timestampNs: Long,
    override val call: Call,
    val ioe: IOException,
  ) : CallEvent() {
    override fun closes(event: CallEvent): Boolean = event is CallStart && call == event.call
  }

  data class Canceled(

    }

    @Override public void callStart(Call call) {
      printEvent("callStart");
    }

    @Override public void proxySelectStart(Call call, HttpUrl url) {
      printEvent("proxySelectStart");
    }

    @Override public void proxySelectEnd(Call call, HttpUrl url, List<Proxy> proxies) {
      printEvent("proxySelectEnd");
    }

    @Override public void dnsStart(Call call, String domainName) {

  override fun canceled(call: Call) = onEvent(Canceled(System.nanoTime(), call))

  override fun satisfactionFailure(
    call: Call,
    response: Response,
  ) = onEvent(SatisfactionFailure(System.nanoTime(), call))

  override fun cacheMiss(call: Call) = onEvent(CacheMiss(System.nanoTime(), call))

  override fun cacheHit(
    call: Call,
    response: Response,