*
   * @since 19.0
   */
  public Optional<Long> lengthIfKnown() {
    return Optional.absent();
  }

  /**
   * Returns the length of this source in chars, even if doing so requires opening and traversing an
   * entire stream. To avoid a potentially expensive operation, see {@link #lengthIfKnown}.
   *
   * <p>The default implementation calls {@link #lengthIfKnown} and returns the value if present. If

   *
   * @since 19.0
   */
  public Optional<Long> lengthIfKnown() {
    return Optional.absent();
  }

  /**
   * Returns the length of this source in chars, even if doing so requires opening and traversing an
   * entire stream. To avoid a potentially expensive operation, see {@link #lengthIfKnown}.
   *
   * <p>The default implementation calls {@link #lengthIfKnown} and returns the value if present. If

    assertThat(UnsignedLongs.remainder(0xfffffffffffffffeL, 5)).isEqualTo(4);
  }

  @GwtIncompatible // Too slow in GWT (~3min fully optimized)
  public void testDivideRemainderEuclideanProperty() {
    // Use a seed so that the test is deterministic:
    Random r = new Random(0L);
    for (int i = 0; i < 1000000; i++) {
      long dividend = r.nextLong();
      long divisor = r.nextLong();

    start();
  }

  // Thread.stop() is okay because all threads started by a test are dying at the end of the test,
  // so there is no object state put at risk by stopping the threads abruptly. In some cases a test
  // may put a thread into an uninterruptible operation intentionally, so there is no other way to
  // clean up these threads.
  @SuppressWarnings("deprecation")
  @Override
  public void tearDown() throws Exception {

Você também pode criar uma variável de ambiente apenas para uma **invocação específica do programa**, que só está disponível para aquele programa e apenas pela duração dele.

Para fazer isso, crie-a na mesma linha, antes do próprio programa:

<div class="termy">

```console

  while (!exhausted()) {
    skip(buffer.size)
  }
}

/**
 * Attempts to exhaust this, returning true if successful. This is useful when reading a complete
 * source is helpful, such as when doing so completes a cache body or frees a socket connection for
 * reuse.
 */
internal fun Source.discard(
  timeout: Int,
  timeUnit: TimeUnit,
): Boolean =
  try {
    this.skipAll(timeout, timeUnit)

import org.jspecify.annotations.NullUnmarked;

/**
 * Utilities for benchmarks.
 *
 * <p>In many cases, we wish to vary the order of magnitude of the input as much as we want to vary
 * the input itself, so most methods which generate values use an exponential distribution varying
 * the order of magnitude of the generated values uniformly at random.
 *
 * @author Louis Wasserman
 */
@NullUnmarked

	letterIdxMax  = 63 / letterIdxBits   // # of letter indices fitting in 63 bits
)

// Random number state.
// We generate random temporary file names so that there's a good
// chance the file doesn't exist yet.
var (
	randN  uint32
	randmu sync.Mutex
)

// Temp files created in default Tmp dir
var globalTestTmpDir = os.TempDir()

import java.util.Set;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Derived suite generators for Guava collection interfaces, split out of the suite builders so that
 * they are available to GWT.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@NullMarked
public final class DerivedGoogleCollectionGenerators {

@SuppressWarnings({
  // @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
  "JUnit4ClassUsedInJUnit3",
  // We use ::iterator so that we test passing a plain Iterable, not a Collection.
  "UnnecessaryMethodReference",
})
public class MultimapPutIterableTester<K, V> extends AbstractMultimapTester<K, V, Multimap<K, V>> {