Add RSocket Interceptors

[rwinch]

Affects: 5.2.0.BUILD-SNAPSHOT

The WebClient supports an ExchangeFilterFunction that allows intercepting the request/response. WebClient also allows providing attributes that can be used by ExchangeFilterFunction for processing. In combination this allows a user to provide an OAuth token via the attributes and have an ExchangeFilterFunction add the token to the request. The ExchangeFilterFunction can also refresh the token (a blocking operation) if the token is expired before sending the original request.

It would be nice to have the ability to have similar features with the RSocket support.

[khngn]

Any progress/plan RSocket interceptors? I'm looking for similar feature of org.springframework.security.oauth2.server.resource.web.reactive.function.client.ServerBearerExchangeFilterFunction to propagate Authentication details for RSocket requester.