How get an immutable Pin from a mutable Pin?
How to apply deref coercion from &mut to & for references that are wrapped inside Pin<>? That is, how to borrow Pin<&mut _> as Pin<&_>?
How to apply deref coercion from &mut to & for references that are wrapped inside Pin<>? That is, how to borrow Pin<&mut _> as Pin<&_>?