code: @Beta
    public final FluentIterable<E> append(E... elements) {
      return from(FluentIterable.concat(getDelegate(), Arrays.asList(elements)));
    }
docs: Returns a fluent iterable whose iterators traverse first the elements of this fluent iterable,
  followed by {@code elements}.
  
  <p><b>{@code Stream} equivalent:</b> {@code Stream.concat(thisStream, Stream.of(elements))}.
  
  @since 18.0