(let manager:make (fun () (...)))
Allows to register events listeners and emit events
Author: @fabien-zoccola
(let em (events:manager:make))
(em.on "myType" (fun (value) (print "This is a callback")))
(em.emit "myType") # => prints "This is a callback" thanks to the registered listener
(let _check_valid (fun (callback) (...)))
Checks if a given callback is valid (is a function or a closure)