This structure is created on entry to the Handler method and is disposed of upon return. It is part of the plug-in infrastructure, rather than the functionally specific REST handler, and fundamental changes to this should be reflected in the Rest HandlerVersion. The object is instantiated, and may be extended by, any given handler. See the inventory handler for an example of this.
If possible, the underlying request/response state is not changed until the handler explicitly issues a Respond call. This ensures that the request/response pair can be safely processed by subsequent, unrelated, handlers even id the agent handler had completed much of its processing. Think of it as a transactional req/resp capability.
1.5.1