* @throws UnsupportedCharsetException if a charset value is present, but no support is available
   *     in this instance of the Java virtual machine
   */
  public Optional<Charset> charset() {
    // racy single-check idiom, this is safe because Optional is immutable.
    Optional<Charset> local = parsedCharset;
    if (local == null) {
      String value = null;
      local = Optional.absent();

import org.junit.jupiter.api.AfterEach
import org.junit.jupiter.api.Test

/**
 * Unit test for [FastFallbackExchangeFinder] implementation details.
 *
 * This test uses [TaskFaker] to deterministically test racy code. Each function in this test has
 * the same structure:
 *
 *  * prepare a set of plans, each with a predictable connect delay
 *  * attempt to find a connection

        thirdSignal.countDown();
        result.set(1, cache.getUnchecked(key));
        doneSignal.countDown();
      }
    }.start();

    // give the second get a chance to run; it is okay for this to be racy
    // as the end result should be the same either way
    thirdSignal.await();
    Thread.yield();

    // Expand!
    CacheTesting.forceExpandSegment(cache, key);

    // should be reading the byte at index 10.
    // We could use a custom InputStream instead to make the read start at index 10, but since this
    // is a racy situation anyway, this behavior seems reasonable.
    assertEquals(-1, in.read());
  }

  private static class AppendableByteSource extends ByteSource {
    private byte[] bytes;

     *       cleared, we know that we're not executing inline any more
     * </ul>
     *
     * All the states where thread != currentThread are identical for our purposes, and so even
     * though it's racy, we don't care which of those values we get, so no need to synchronize.
     */
    @CheckForNull @LazyInit Thread thread;

    /** Only used by the thread associated with this object */

* Dodać nową funkcję.
    * Upewnij się, że dodajesz testy.
    * Upewnij się, że dodajesz dokumentację, jeśli jest to istotne.

## Pomóż w utrzymaniu FastAPI

Pomóż mi utrzymać **FastAPI**! 🤓

Jest wiele pracy do zrobienia, a w większości przypadków **TY** możesz to zrobić.

Główne zadania, które możesz wykonać teraz to:

			os.Exit(2)
		}
	}()
	return func() {
		close(cc)
	}
}

func assertNoActive(t *testing.T, c *Connection) {
	t.Helper()
	// Tiny bit racy for tests, but we try to play nice.
	for i := 10; i >= 0; i-- {
		runtime.Gosched()
		stats := c.Stats()
		if stats.IncomingStreams != 0 {
			if i > 0 {
				time.Sleep(100 * time.Millisecond)
				continue

  @LazyInit
  @CheckForNull
  transient ImmutableSortedSet<E> descendingSet;

  /** @since 12.0 */
  @GwtIncompatible // NavigableSet
  @Override
  public ImmutableSortedSet<E> descendingSet() {
    // racy single-check idiom
    ImmutableSortedSet<E> result = descendingSet;
    if (result == null) {
      result = descendingSet = createDescendingSet();
      result.descendingSet = this;
    }
    return result;

      super(Ordering.natural());
      this.domain = domain;
    }

    @LazyInit @CheckForNull private transient Integer size;

    @Override
    public int size() {
      // racy single-check idiom
      Integer result = size;
      if (result == null) {
        long total = 0;
        for (Range<C> range : ranges) {
          total += ContiguousSet.create(range, domain).size();

      super(Ordering.natural());
      this.domain = domain;
    }

    @LazyInit @CheckForNull private transient Integer size;

    @Override
    public int size() {
      // racy single-check idiom
      Integer result = size;
      if (result == null) {
        long total = 0;
        for (Range<C> range : ranges) {
          total += ContiguousSet.create(range, domain).size();