}

  /**
   * A builder for creating {@code ImmutableSet} instances. Example:
   *
   * <pre>{@code
   * static final ImmutableSet<Color> GOOGLE_COLORS =
   *     ImmutableSet.<Color>builder()
   *         .addAll(WEBSAFE_COLORS)
   *         .add(new Color(0, 191, 255))
   *         .build();
   * }</pre>
   *
   * <p>Elements appear in the resulting set in the same order they were first added to the builder.

   * ("constant lists"). Example:
   *
   * <pre>{@code
   * public static final ImmutableList<Color> GOOGLE_COLORS
   *     = new ImmutableList.Builder<Color>()
   *         .addAll(WEBSAFE_COLORS)
   *         .add(new Color(0, 191, 255))
   *         .build();
   * }</pre>
   *
   * <p>Elements appear in the resulting list in the same order they were added to the builder.

   * in the same order as they appeared in this fluent iterable. Example usage:
   *
   * <pre>{@code
   * Color red = new Color("red", 255, 0, 0);
   * ...
   * FluentIterable<Color> allColors = FluentIterable.from(ImmutableSet.of(red, green, blue));
   *
   * Map<String, Color> colorForName = allColors.uniqueIndex(toStringFunction());
   * assertThat(colorForName).containsEntry("red", red);
   * }</pre>
   *

   * Example usage:
   *
   * <pre>{@code
   * Color red = new Color("red", 255, 0, 0);
   * ...
   * ImmutableSet<Color> allColors = ImmutableSet.of(red, green, blue);
   *
   * ImmutableMap<String, Color> colorForName =
   *     uniqueIndex(allColors, c -> c.toString());
   * assertThat(colorForName).containsEntry("red", red);
   * }</pre>

   * in the same order as they appeared in this fluent iterable. Example usage:
   *
   * <pre>{@code
   * Color red = new Color("red", 255, 0, 0);
   * ...
   * FluentIterable<Color> allColors = FluentIterable.from(ImmutableSet.of(red, green, blue));
   *
   * Map<String, Color> colorForName = allColors.uniqueIndex(toStringFunction());
   * assertThat(colorForName).containsEntry("red", red);
   * }</pre>
   *

   * The HTTP <a
   * href="https://wicg.github.io/user-preference-media-features-headers/#sec-ch-prefers-color-scheme">{@code
   * Sec-CH-Prefers-Color-Scheme}</a> header field name.
   *
   * <p>This header is experimental.
   *
   * @since 31.0
   */
  public static final String SEC_CH_PREFERS_COLOR_SCHEME = "Sec-CH-Prefers-Color-Scheme";

  /**
   * The HTTP <a