Why does `parse` expects callers to manually pass `T` when it's always `TokenClaims`?

[Jasperav]

I don't understand why the parse method on Parser not just returns a TokenClaims rather than T. TokenClaims is also not publicly accessible so I have to copy paste the struct in my project to make it work, I don't think this is ergonomic for all crates which calls the parse method to manually add a struct.