Writing an iOS app nowadays is pretty simple, however, a performant one requires more effort in many aspects from algorithm optimization to system related actions. The rule of thumb for most of cases is to keep heavy, time-consuming jobs away from main thread yet ensure that calls to UIKit or UI-related happen in the main thread. That helps the app be responsive and avoid sluggishness while using to bring a better experience to users. Dispatching jobs to the corresponding thread is actually d...
