How to use a Float Action Button in Xamarin.forms with a PCL project form code sharing?

I'm new in Xamarin, Xamarin.Forms and C# platform.

I'm making some experiments with these technologies and now I'm searching about how to use platform specific UI components in Xamarin.Forms with a PCL project for code sharing.

Searching in the web I found some implementations of FAB button (example), but these implementations are deprecated or abandoned.

I know that is possible to Embed Native Controls into Xamarin.Forms, but this approach uses a SAP project...

My question is: Is there a way to use a FAB button (or some other platform specific UI control) into a Xamarin.Forms solution with a PCL project for code sharing? If yes, what will be the behavior in other platforms? I hope that FAB button does not appear on the iOS UI.

Thanks for the help.