title: What is AppBar vs ToolBar?
body: <p>All the material-ui examples show Toolbar inside Appbar. Why not just Appbar? What's the difference between the two?</p>
  
  <p><a href="https://material.io/design/components/" rel="noreferrer">https://material.io/design/components/</a> does <em>not</em> have Toolbar component, only "App bars: top".</p>
  
  <p><a href="https://material.io/develop/web/components/toolbar/" rel="noreferrer">https://material.io/develop/web/components/toolbar/</a> says "The existing MDCToolbar component and styles will be removed in a future release"</p>
  
  <p>So will material-ui Toolbar go away eventually?</p>