title: Difference between onGenerateRoute and routes in Flutter
body: <p>What is the benefit or use case of <code>onGenerateRoute</code> and routes in Flutter.</p>
  <p>In my application in first page inside <code>MaterialApp</code> we can define routes for our Application the same thing we can define with <code>onGenerateRoute</code>.</p>
  <p>Both are used for NamedRoute.</p>
  <p>I am unsure, in which scenario I need to use routes and in which scenario I need to use <code>onGenerateRoute</code>?</p>