Multi get can fail and return a null StatusCode

Found that performing a multi-get during a rebalance had a couple of issue when the code returns from the following line.

https://github.com/couchbase/couchbase-net-client/blob/4642a9d3ef32d5a00bcb458f108c8c002c4b1535/src/Enyim.Caching/Memcached/Protocol/Binary/MultiGetOperation.cs#L185

Client code is using client.ExecuteGet(<array of keys>)

The main issue is that the 'result.Fail' ends up back with the client and StatusCode == null, even though there's a "not my vbucket" status (7) in response.StatusCode.

Minor issue is that the result.Fail message doesn't get formatted to include the correlationId, always prints

.

I've a draft patch that ensures the StatusCode is passed through so that the client can see the failure is not-my-vbucket and issue a retry.

With my draft patch though I couldn't seem to get the StatusCode passed through without creating an "rv" and returning that.

Basically:

result.StatusCode = response.StatusCode;
return result.Fail(...);

and

this.StatusCode = response.StatusCode;
return result.Fail(...)

still returned StatusCode of null?

(patch attached soon)