Add extension support to tonic reflection server

[fracek]

Feature Request

Crates

• tonic-reflection

Motivation

grpcurl requires the reflection server to implement all reflection methods to resolve types, including all_extension_numbers_of_type. Since the server does not implement these two methods, grpcurl won't resolve the types.

Proposal

Can we implement these two methods? This issue is quite important to me so I'm willing to contribute to it.

Alternatives

Add a flag or crate feature to return an empty response.