module Kernel

def Sync(&block)

@asynchronous Will block until given block completes executing.
@public Since `stable-v1`.

@parameter task [Async::Task] The task that is executing the given block.
@yields {|task| ...} The block that will execute asynchronously.

Run the given block of code synchronously, but within a reactor if not already in one. 
def Sync(&block)
	if task = ::Async::Task.current?
		yield task
	elsif scheduler = Fiber.scheduler
		::Async::Task.run(scheduler, &block).wait
	else
		# This calls Fiber.set_scheduler(self):
		reactor = Async::Reactor.new
		
		begin
			return reactor.run(finished: ::Async::Condition.new, &block).wait
		ensure
			Fiber.set_scheduler(nil)
		end
	end
end