How can I create a custom Xamarin.Forms component that can be creating through xaml?

My apologies if this question has already been answered. I'd like to create a tab component with some specific behaviors based on Xamarin.Forms where the tab definition xaml is something similar to:

<Tab OnTabChange="Some_Event_Handler">
<Tabs>
<Tab Text="xxx" />
<Tab Text="yyy" />
</Tab>
</Tab>

Are there any resources available that use custom xaml that I can review?

Any insight is greatly appreciated.