* used. HTTP/1.x connections can carry either zero or one streams. HTTP/2 connections can carry any
 * number of streams, dynamically configured with `SETTINGS_MAX_CONCURRENT_STREAMS`. A connection
 * currently carrying zero streams is an idle stream. We keep it alive because reusing an existing
 * connection is typically faster than establishing a new one.
 *

        new Builder<String, Integer>().put(immutableEntry("one", 1)).build();
    assertEquals(asList(1), multimap.get("one"));
  }

  public void testBuilder_withImmutableEntryAndNullContents() {
    Builder<String, Integer> builder = new Builder<>();
    assertThrows(
        NullPointerException.class, () -> builder.put(immutableEntry("one", (Integer) null)));

  /**
   * A collector that converts a stream of zero or one elements to an {@code Optional}.
   *
   * @throws IllegalArgumentException if the stream consists of two or more elements.
   * @throws NullPointerException if any element in the stream is {@code null}.
   * @return {@code Optional.of(onlyElement)} if the stream has exactly one element (must not be

       *   setFuture called on it: Neither of those can happen until we've finished processing all
       *   the completed inputs. And we're still processing at least one input, the one that
       *   triggered handleException.)
       *
       * TODO(cpovirk): Think about whether we could/should use Verify to check the return value of
       * addCausalChain.
       */

   * element, and the overall size of the collection, by one.
   *
   * <p>To both add the element and obtain the previous count of that element, use {@link
   * #add(Object, int) add}{@code (element, 1)} instead.
   *
   * @param element the element to add one occurrence of; may be null only if explicitly allowed by
   *     the implementation

 * domains which are both public suffixes and addressable as hosts; {@code "uk.com"} is one example.
 * Using the subset of public suffixes that are {@linkplain #isRegistrySuffix() registry suffixes},
 * one can get a better result, as only a few registry suffixes are addressable. However, the most

  /** Test an empty collection. */
  ZERO(0),
  /** Test a one-element collection. */
  ONE(1),
  /** Test a three-element collection. */
  SEVERAL(3),
  /*
   * TODO: add VERY_LARGE, noting that we currently assume that the fourth
   * sample element is not in any collection
   */

  ANY(ZERO, ONE, SEVERAL);

  private final Set<Feature<? super Collection>> implied;

  /** Test an empty collection. */
  ZERO(0),
  /** Test a one-element collection. */
  ONE(1),
  /** Test a three-element collection. */
  SEVERAL(3),
  /*
   * TODO: add VERY_LARGE, noting that we currently assume that the fourth
   * sample element is not in any collection
   */

  ANY(ZERO, ONE, SEVERAL);

  private final Set<Feature<? super Collection>> implied;

    worked everywhere that I know of except for one place: when running the GWT
    util.concurrent tests under Guava.

    The problem is that GWT responds poorly to two .gwt.xml files in the same
    Java package; see
    https://groups.google.com/g/google-web-toolkit-contributors/c/CqYH59Dt_rQ/m/uVGW1QdUsXUJ
    for details.

    The summary is that it ignores one file in favor of the other.

    worked everywhere that I know of except for one place: when running the GWT
    util.concurrent tests under Guava.

    The problem is that GWT responds poorly to two .gwt.xml files in the same
    Java package; see
    https://groups.google.com/g/google-web-toolkit-contributors/c/CqYH59Dt_rQ/m/uVGW1QdUsXUJ
    for details.

    The summary is that it ignores one file in favor of the other.