I have a package which has a function `Do[T comparable](a, b []T) Result`.
I have a struct:
```go
type N struct {
x int
y int
t string
}
```
Is it possible to make `N` comparable; in particular by a field of my choice, e.g., `t`?
Or will I have to make, say, `DoFunc(a, b []N, eq func(i, j N) bool) Result` with, say,
`func eq(i, j N) { return i.t == j.t }`?