Fix 35faf1f by only sending innerTask's progressValue to downstream, not from parentTask.
Fix 35faf1f by only sending innerTask's progressValue to downstream, not from parentTask.

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