title: what is `optimistic updates` in front-end development
body: <p>I'm reading the <a href="https://redux.js.org/introduction/motivation" rel="noreferrer">intro to <code>redux</code> pattern</a>, and there is the following paragraph there:</p>
  
  <blockquote>
    <p>... consider the new requirements becoming common in front-end product
    development, such as handling optimistic updates, rendering on the
    server, fetching data before performing route transitions, and so on.</p>
  </blockquote>
  
  <p>My question is what is <em>optimistic updates</em> here?</p>