Toast provider postion

[code100]

Hi,

Thanks for building the library, it is really handy!

I'd like to know of how to postion a toast in the center within toast provider. Current toast provider example only shows toast on top right of screen.

It would be great if you could share more examples with toaster provider. I guess it's very common use, for exmaple, after saving an item, there is a toast popup with sucessful message.

Thanks
David