title: react router's location state becomes undefined on change of route
body: <p>I want to store <code>url query</code>  as a state on location.</p>
  
  <pre><code>~   history.push({
  +     ...history.location,
  +     search: query.toString(),
  +     state: {
  +       myState: query.toString(),
  +     },
  +   })
  </code></pre>
  
  <p>I suspect get state when a route change, but <code>state</code> become <code>undefined</code> when I back from other route.</p>