class Async::Promise

def initialize

Create a new promise. 
def initialize
	# nil = pending, :completed = success, :failed = failure, :cancelled = cancelled:
	@resolved = nil
	
	# Stores either the result value or the exception:
	@value = nil
	
	# Track how many fibers are currently waiting:
	@waiting = 0
	
	@mutex = Mutex.new
	@condition = ConditionVariable.new
end