anchor.diff:  * `setupMetadata(Object, MimeType)` -- other metadata to include in the `SETUP`.
   
   For data, the default mime type is derived from the first configured `Decoder`. For
  -metadata, the default mime type is composite metadata which allows multiple metadata
  -value and mime type pairs per request. Typically both don't need to be changed.
  +metadata, the default mime type is
  +{gh-rsocket-extentions}/CompositeMetadata.md[composite metadata] which allows multiple
  +metadata value and mime type pairs per request. Typically both don't need to be changed.
   
   Data and metadata in the `SETUP` frame is optional. On the server side,
  -a `@ConnectMapping` methods can be used to handle the start of a connection and the
  -content of the `SETUP` frame. Metadata may include connection level security info.
  +<<rsocket-annot-connectmapping>> methods can be used to handle the start of a
  +connection and the content of the `SETUP` frame. Metadata may be used for connection
  +level security.
   
   
   [[rsocket-requester-client-strategies]]
  
positive.code: ----
  	String securityToken = ... ;
  	ViewBox box = ... ;
  
  	Flux<AirportLocation> locations =
  		requester.route("locate.radars.within")
  			.metadata(securityToken, "message/x.rsocket.authentication.bearer.v0")
  			.data(viewBox)
  			.retrieveFlux(AirportLocation.class);
  
  
negative.code: The `spring-messaging` module contains the following:
  
  * <<rsocket-requester>> -- fluent API to make requests through an `io.rsocket.RSocket`
    with data and metadata encoding/decoding.
  * <<rsocket-annot-responders>> -- `@MessageMapping` annotated handler methods for
    responding.
  
  The `spring-web` module contains `Encoder` and `Decoder` implementations such as Jackson
  CBOR/JSON, and Protobuf that RSocket applications will likely need. It also contains the
  