Unexpose immutable fields in stack.Route

This change sets the inner `routeInfo` struct to be a named private member
and replaces direct access with access through getters. Note that direct
access to the fields of `routeInfo` is still possible through the `RouteInfo`
struct.

Fixes #4902

PiperOrigin-RevId: 364822872
16 files changed
tree: 6d30b552411662acf8d87b66e801ebb4e29387dd
  1. AUTHORS
  2. LICENSE
  3. go.mod
  4. go.sum
  5. pkg/