Create an SDK for iOS and Android using Xamarin

Hi All,
I am building a unique app where I have some of the logic in forms and many
specific logic (services, background tasks, bluetooth logic) in each platform project.
Could I generate my own SDK using Xamarin that developers can use it as an API in native iOS and Android apps?
Another question I have is about Prism, is it a recommended platform or does it come with a performance hit?