code: public Spliterator<E> spliterator() {
          return Spliterators.spliterator
              (this, (Spliterator.ORDERED |
                      Spliterator.NONNULL |
                      Spliterator.CONCURRENT));
      }
docs: Returns a {@link Spliterator} over the elements in this queue.
  
  <p>The returned spliterator is
  <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
  
  <p>The {@code Spliterator} reports {@link Spliterator#CONCURRENT},
  {@link Spliterator#ORDERED}, and {@link Spliterator#NONNULL}.
  
  @implNote
  The {@code Spliterator} implements {@code trySplit} to permit limited
  parallelism.
  
  @return a {@code Spliterator} over the elements in this queue
  @since 1.8