title: Double rendering useEffect reactjs
body: <p>I try to get async fetch data with a react context provider
  I don't understand why there is 2 rendering of child component which use context, with a first initial context state and second with data fetched.
  Is there any proper way to avoid it ?</p>
  
  <p><a href="https://codesandbox.io/s/brave-chandrasekhar-1w5xv?fontsize=14&amp;hidenavigation=1&amp;theme=dark" rel="nofollow noreferrer">codesandbox example</a></p>