We've got parameters here and usually we name them Raw when they're
represented by json.RawMessage which is not the case here, so make it a bit
more friendly (the type itself is only used in client internals, so rename is
not a huge problem).
It's absolutely irrelevant for the client and request/response packages should
only contain code that is useful on both sides of the conversation. It's OK
for client tests to reuse this code, but the package is used by external
developers and they shouldn't be bothered with it. Nothing changed
functionally here except WSClient simplification. Fixes#2236.
It's not needed any more with Go 1.13 as we have wrapping/unwrapping in base
packages. All errors.Wrap calls are replaced with fmt.Errorf, some strings are
improved along the way.
Mostly as is, no real effort done yet to optimize them, so there are still a
lot of duplicates there, but at least we sort them out into different smaller
packages.