Fix 4400589 by allowing success() to handle any innerTask types and silence wrong Error type as nil whenever needed.
Fix 4400589 by allowing success() to handle any innerTask types and silence wrong Error type as nil whenever needed.

msdgwzhy6/SwiftTask,marinehero/SwiftTask,msdgwzhy6/SwiftTask,iosyoujian/SwiftTask,marinehero/SwiftTask,msdgwzhy6/SwiftTask,ReactKit/SwiftTask,ReactKit/SwiftTask,msdgwzhy6/SwiftTask,luzefeng/SwiftTask,luzefeng/SwiftTask,marinehero/SwiftTask,luzefeng/SwiftTask,iosyoujian/SwiftTask,luzefeng/SwiftTask,iosyoujian/SwiftTask,iosyoujian/SwiftTask,marinehero/SwiftTask,ReactKit/SwiftTask