*
   * {@snippet :
   * 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);
   * }
   *

   *
   * {@snippet :
   * 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);
   * }
   *

   * Example usage:
   *
   * {@snippet :
   * 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);
   * }
   *

   * Example usage:
   *
   * {@snippet :
   * 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);
   * }
   *