Many apps save state and progress automatically in the background. Mobile apps save what page you're on even after the apps are cleared out of RAM. OneNote and Word for iOS save documents automatically. Elementary OS apps are supposed to open where the user left off last time. But if non-interruptive saving is possible, why does auto-save in desktop word processors require the user to wait for saving to finish?
This process doesn't seem to be instantaneous, for some reason. Scrolling position in Safari Reader Mode is a bit off after you press the home button while scrolling.
How does non-interruptive autosave work?