Xamarin Forms WebView Pinch To Zoom

Hi,

I am new in Xamarin Forms,
I have HTML Pages, that's display in Xamarin Forms App (iOS/Android) using WebView.
All is working fine.
But i need to implement Pinch To Zoom for android.
not in build functionality like:-

this.Control.Settings.BuiltInZoomControls = true;
this.Control.Settings.DisplayZoomControls = true;

I have implement Zoom In/Out buttons Like:-
https://stackoverflow.com/questions/41328371/zoom-text-of-webview-in-xamarin-forms

and it's working fine.

Same functionality i need to implement using pinch to zoom.

Please Help.

Thanks