title: In Xamarin Forms how can I set the font of a label to Medium (System font)
body: <p>I would like to use SF Pro (iOS) and Roboto (Android) which are the system fonts. Both have medium but I cannot see any way to set these for a label.</p>
  <p>I think I might need a Label custom renderer and would appreciate any advice / suggestions.</p>
  <p>Here are some references:</p>
  <p><a href="https://qiita.com/aqubi/items/3a1e668f4f78d4ad0db7" rel="nofollow noreferrer">https://qiita.com/aqubi/items/3a1e668f4f78d4ad0db7</a></p>
  <p><a href="https://forums.xamarin.com/discussion/97446/set-font-weight-on-label" rel="nofollow noreferrer">https://forums.xamarin.com/discussion/97446/set-font-weight-on-label</a></p>
  <p><a href="https://github.com/xamarin/Xamarin.Forms/issues/8035" rel="nofollow noreferrer">https://github.com/xamarin/Xamarin.Forms/issues/8035</a></p>