code: @Beta
    public static OptionalInt findLast(IntStream stream) {
      // findLast(Stream) does some allocation, so we might as well box some more
      java.util.Optional<Integer> boxedLast = findLast(stream.boxed());
      return boxedLast.isPresent() ? OptionalInt.of(boxedLast.get()) : OptionalInt.empty();
    }
docs: Returns the last element of the specified stream, or {@link OptionalInt#empty} if the stream is
  empty.
  
  <p>Equivalent to {@code stream.reduce((a, b) -> b)}, but may perform significantly better. This
  method's runtime will be between O(log n) and O(n), performing better on <a
  href="http://gee.cs.oswego.edu/dl/html/StreamParallelGuidance.html">efficiently splittable</a>
  streams.
  
  @see IntStream#findFirst()
  @throws NullPointerException if the last element of the stream is null