JAX-RS Client Library
Consider the use case where an Apache Isis app emits "thin" events to an ESB, for example using the Outbox Publisher. The ESB then queries back to the Apache Isis app to get extra info in a canonical DTO form in order to continue processing.
|for more on this use case, try searching on "fat vs thin events".|
This library, then, provides a bit of code to construct the correct
Accept-Type headers, in a format that is then interpreted by an application-specific implementation of ContentMappingService.