sqlite.conn visibility

Hi, amazing project! thank you so much for your work!

I would like to create custom functions in go using Xsqlite3_create_function() from a db opened using the standard sql package. Currently I don't see any good way to access the required sqlite.conn.tls and sqlite.conn.db vars that are hidden behind the private struct sqlite.conn.

My main idea is to obtain this struct in the following way:

sql.Open -> *sql.db -> db.Conn() -> *sql.Conn -> conn.Raw()

When you perform a sql.Conn.Raw() it calls a callback function passing an interface{} of the driver's connection struct (according the official go doc). But I cannot perform on this struct (sqlite.conn) a type assertions because of visibility.

I was wondering if you can make it public. That will enable everyone to register custom functions, vfs, and so much more using the functions in modernc.org/sqlite/lib! What do you think? is there a better way I am missing?