class Async::Scheduler

@parameter fiber [Fiber] The fiber to unblock.
@parameter blocker [Object] The object that was blocking the fiber.

@asynchronous May be called from any thread.
@public Since *Async v2* and *Ruby v3.1*.

Unblock a fiber that was previously blocked.

def unblock(blocker, fiber)
	# $stderr.puts "unblock(#{blocker}, #{fiber})"
	
	# This operation is protected by the GVL:
	if selector = @selector
		selector.push(fiber)
		selector.wakeup
	end
end