So much for the Android hardcore's oft parroted "iOS doesn't do true multitasking" ...whatever... it can switch apps waaaaayyyyyyyyyyyyyyyyyyyyy faster.
It's faking it by pretty much taking a screenshot before being suspended/killed in the background then restoring the screenshot upon app relaunch so it's not true multitasking. For professionals that use apps like SSH, RDP, VNC, etc. they can't actively run in the background so iOS is more like an iPod than a PC replacement contrary to Timothy Cook's outlandish claims.
https://developer.apple.com/library...GforiPhoneOS/PreservingandRestoringState.html
Preserving and Restoring State
View controllers play an important role in the state preservation and restoration process. State preservation records the configuration of your app before it is suspended so that the configuration can be restored on a subsequent app launch.