Should come up with plan for injection on client side

I don't know if maybe we should tag this with WINK-166, but the RuntimeContext should get set before invoking the client's request's HandlerContext chain. A handler such as AcceptHeaderHandler can invoke a Provider's isReadable (say wink-json-providers) before the ProvidersRegistry is put on the RuntimeContextTLS during the readEntity/writeEntity on the client.

Should implement UriInfo and other JAX-RS interfaces to allow the widest range of readers/writers on the client. Otherwise, if a provider is injected with one of the Context interfaces, a NPE will occur for them as well (i.e. wink-json-providers)

I haven't thought this all the way through but another problem is that HttpHeaders is really intended for use on the server side only. I imagine some of the generic provider logic for entity providers would not work correctly (say a HttpHeaders.getAcceptableMediaTypes() is called during the writeTo() of an entity provider).