Unreleased

Add [Fiber.map_reduce_seq] (#14, @rgrinberg)
Make [Fiber.both] concurrent (#32, @rgrinberg)
Add [Fiber.Lazy] (#36, #rleshchinskiy)
Rename Fiber.Pool.stop to Fiber.Pool.close (#13, @rgrinberg)
Remove Make_map_traversals and introduce Make_parallel_map. The new functor requires a small base API to provide a parallel map on maps and parallel iteration is still available via parallel_iter_seq. (#22, @rgrinberg)
Remove Nonempty_list from the scheduler API. It's replaced with a regular list and there's no issues with providing an empty list (#19, @rgrinberg)

3.7.0