Main.hx:3: characters 36-55 : c : { test : String } -> Void should be Null<js.PromiseCallback<Int, Void>>
Main.hx:3: characters 36-55 : c : { test : String } -> Void should be js.PromiseCallback<Int, Void>
Main.hx:3: characters 36-55 : c : { test : String } -> Void should be haxe.extern.EitherType<Int -> Void, Int -> js.Promise<Void>>
Main.hx:3: characters 36-55 : For function argument 'fulfillCallback'