Add :finish_in_order option

[shaicoleman]

See #338 for discussion

[grosser]

can these be local variables ?

[shaicoleman]

You can't use local variables, as they need to maintain the state between invocations.
As they are being called via a class method, it can't use instance variables either.
The options are dup'ed so works even when invoked multiple times with the same options

[grosser]

can do this in the loop to not have the code twice ?

[shaicoleman]

To do it in the loop, you would have to store the item first, e.g. something like this:
This is a bit more readable, but uses a tiny bit more memory.

    def instrument_finish_in_order(item, index, result, options)
      options[:mutex].synchronize do
        options[:finish_items] ||= []
        options[:finish_items_done] ||= []
        options[:finish_index] ||= 0
        options[:finish_items][index] = item
        options[:finish_items_done][index] = true
        break unless index == options[:finish_index]
        index.upto(options[:finish_items].size).each do |old_index|
          break unless options[:finish_items_done][old_index]
          old_item = options[:finish_items][old_index]
          options[:finish].call(old_item, old_index, result)
          options[:finish_index] += 1
        end
      end
    end

Let me know if you prefer this version and I'll update the PR

[grosser]

FYI refactored #340

[grosser]

lmk if you can spot any more issues, otherwise I'll merge this and then release a new minor 🎉

[grosser]

1.24.0