init = true;
          }
        } finally {
          busy = 0;
        }
        if (init) break;
      } else if (casBase(v = base, fn(v, x))) break; // Fall back on using base
    }
  }

  /** Sets base and all cells to the given value. */
  final void internalReset(long initialValue) {
    Cell[] as = cells;
    base = initialValue;
    if (as != null) {
      int n = as.length;

        | ((source[offset + 3] & 0xFF) << 24);
  }

  /**
   * Indicates that the load and store operations will be very efficient because of use of VarHandle
   * or Unsafe. May be useful for calling code to fall back on an alternative implementation that is
   * slower than those implementations but faster than the pure-Java mask-and-shift.
   */
  static boolean usingFastPath() {
    return byteArray.usesFastPath();
  }

        Entry<Object, Object> entry = warmed.get(i - WARMUP_MIN);
        assertTrue(cache.asMap().containsKey(entry.getKey()));
        assertTrue(cache.asMap().containsValue(entry.getValue()));
        // this getUnchecked() call shouldn't be a cache miss; verified below
        assertEquals(entry.getValue(), cache.getUnchecked(entry.getKey()));
      }
      assertEquals(WARMUP_SIZE, cache.stats().missCount());
      checkValidState(cache);
    }

   * {@link MoreExecutors#directExecutor}. Normally, when the first future completes, all the other
   * tasks would be called recursively. Here, we detect that the delegate executor is executing
   * inline, and maintain a queue to dispatch tasks iteratively. There is one instance of this class
   * per call to submit() or submitAsync(), and each instance supports only one call to execute().
   *

	all = make([]*peerRESTClient, len(hosts))
	for i, host := range hosts {
		if host == nil {
			continue
		}
		all[i] = newPeerRESTClient(host, endpoints.FindGridHostsFromPeer(host))
		remote = append(remote, all[i])
	}
	if len(all) != len(remote)+1 {
		peersLogIf(context.Background(), fmt.Errorf("Expected number of all hosts (%v) to be remote +1 (%v)", len(all), len(remote)), logger.WarningKind)
	}

   * iterable supports it. Note that it is <i>not</i> possible to delete the last skipped element by
   * immediately calling {@code remove()} on that iterator, as the {@code Iterator} contract states
   * that a call to {@code remove()} before a call to {@code next()} will throw an {@link
   * IllegalStateException}.
   *
   * <p><b>{@code Stream} equivalent:</b> {@link Stream#skip}
   *
   * @since 3.0
   */

 * **ExchangeFinder** chooses which connection carries each exchange. Where possible it will use the same connection for all exchanges in a single call. It prefers reusing pooled connections over establishing new connections.      

#### Per-Connection Locks

     * null} if {@code remove()} or {@code add()} has been called more recently than either. We use
     * this to determine which stack to pop from on a call to {@code remove()} (or to pop from and
     * push to on a call to {@code set()}).
     */
    @Nullable Stack<E> stackWithLastReturnedElementAtTop = null;

    MultiExceptionListIterator(List<E> expectedElements) {

  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**).