* href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Viewport-Width">{@code
   * Viewport-Width}</a> header field name.
   *
   * @since 31.0
   */
  public static final String VIEWPORT_WIDTH = "Viewport-Width";

  /**
   * The HTTP <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Width">{@code
   * Width}</a> header field name.
   *
   * @since 31.0
   */

  public static CharMatcher invisible() {
    return Invisible.INSTANCE;
  }

  /**
   * Determines whether a character is single-width (not double-width). When in doubt, this matcher
   * errs on the side of returning {@code false} (that is, it tends to assume a character is
   * double-width).
   *
   * <p><b>Note:</b> as the reference file evolves, we will modify this matcher to keep it up to
   * date.
   *

  public static CharMatcher invisible() {
    return Invisible.INSTANCE;
  }

  /**
   * Determines whether a character is single-width (not double-width). When in doubt, this matcher
   * errs on the side of returning {@code false} (that is, it tends to assume a character is
   * double-width).
   *
   * <p><b>Note:</b> as the reference file evolves, we will modify this matcher to keep it up to
   * date.
   *

   * requests become more likely to trigger expensive operations (a more extreme case of this
   * example is when a server has just booted, and it is mostly busy with getting itself up to
   * speed).
   *
   * To deal with such scenarios, we add an extra dimension, that of "past underutilization",
   * modeled by "storedPermits" variable. This variable is zero when there is no underutilization,

   *   absent.
   */

  /**
   * If {@code key} is not already associated with a value or if {@code key} is associated with
   * zero, associate it with {@code newValue}. Returns the previous value associated with {@code
   * key}, or zero if there was no mapping for {@code key}.
   */
  long putIfAbsent(K key, long newValue) {
    while (true) {

  private Atomics() {}

  /**
   * Creates an {@code AtomicReference} instance with no initial value.
   *
   * @return a new {@code AtomicReference} with no initial value
   */
  public static <V> AtomicReference<@Nullable V> newReference() {
    return new AtomicReference<>();
  }

  /**
   * Creates an {@code AtomicReference} instance with the given initial value.
   *
   * @param initialValue the initial value

    ImmutableSet<HashCode> hashCodes =
        ImmutableSet.of(
            SIP_WITH_KEY.hashBytes(col1),
            SIP_WITH_KEY.hashBytes(col2),
            SIP_WITH_KEY.hashBytes(col3));
    assertEquals(3, hashCodes.size());
  }

  public void testToString() {
    assertEquals("Hashing.sipHash24(" + K0 + ", " + K1 + ")", SIP_WITH_KEY.toString());

      INSTANCE;

      /*
       * Static final fields are presumed to be fastest, based on our experience with
       * UnsignedBytesBenchmark. TODO(cpovirk): benchmark this
       */
      /*
       * A CopyOnWriteArraySet<WeakReference> is faster than a newSetFromMap of a MapMaker map with
       * weakKeys() and concurrencyLevel(1), even up to at least 12 cached exception types.
       */

  @Override
  SortedMap<K, V> create(Object... elements);

  /**
   * Returns an entry with a key less than the keys of the {@link #samples()} and less than the key
   * of {@link #belowSamplesGreater()}.
   */
  Entry<K, V> belowSamplesLesser();

  /**
   * Returns an entry with a key less than the keys of the {@link #samples()} but greater than the
   * key of {@link #belowSamplesLesser()}.
   */

    super(message);
  }

  /**
   * Creates a new instance with the given detail message and cause. Prefer to provide a
   * non-nullable {@code cause}, as many users expect to find one.
   */
  public UncheckedExecutionException(@CheckForNull String message, @CheckForNull Throwable cause) {
    super(message, cause);
  }

  /**
   * Creates a new instance with {@code null} as its detail message and the given cause. Prefer to