code: public static <E> Set<E> newIdentityHashSet() {
      return Collections.newSetFromMap(Maps.<E, Boolean>newIdentityHashMap());
    }
docs: Creates an empty {@code Set} that uses identity to determine equality. It compares object
  references, instead of calling {@code equals}, to determine whether a provided object matches
  an element in the set. For example, {@code contains} returns {@code false} when passed an
  object that equals a set member, but isn't the same instance. This behavior is similar to the
  way {@code IdentityHashMap} handles key lookups.
  
  @since 8.0