initWithNibName: vs initWithCoder: for UIVIewController

gistfile1.txt

[UIViewController initWithNibName:] is only used when the view controller is created directly in code instead of in storyboard. 
The nib file with the nib name if actually for the view of the controller (in fact there is no option for view controller when creating new User Interface file in Xcode), 
so unarchiving the nib file will call
[UIView initWithCoder:]  instead of [UIViewController initWithCoder:]. 
The unarchiving will only be triggered when the view property
of the view controller is accessed for the first time, because [UIView initWithCoder:] is called by [UIViewController loadView]. 

On the other hand, when UIViewController is created in storyboard, either automatically by storyboard or manually by calling 
[UIStoryboard instantiateViewControllerWithItentifier:], 
[UIViewController initWithCoder:] will be called to unarchive the view controller object from the storyboard.