Usage when storing `Out` in a struct

[PSeitz]

I tried these two variants without success. Is this something that's supported?

struct Keep<'a>{
   out: Out<'a>` 
}

struct Keep<'a>{
   out: &mut Out<'a>` 
}

[kupiakos]

This needs to specify a T value for what the out reference should write, like:

struct Keep<'a> {
    out: Out<'a, u32>,
}

or

struct Keep<'a, T> {
    out: Out<'a, T>,
}