ProtocolsHandler methods need to be implemented in helpers.

[twittner]

The ProtocolsHandler trait has several methods with default implementations, in particular

• inject_address_change
• inject_listen_upgrade_error

It also has some helper functionality like map_in, map_out or select. The traits impls from those do not implement these methods by forwarding the calls to their inner impls. ProtocolsHandler types which have been mapped or selected, will thus miss those callback.

[romanb]

Closed by #1707, though there may be more refinements later.