Fix XCLAIM exception on nil result

[eadz]

See issue #905

[byroot]

In which circumstances? Could you add a unit test to show it and ensure it won't be broken again in the future?

[eadz]

@byroot Happy to add tests, but I was unable to see any tests that tests the lamdas, so a little unsure where to start. Are there any tests at all for those lamdas and/or respone processing from the streams stuff?

The issue #905 has the redis call that will trigger the error. You may need to create the stream and consumer group first, but then in that response you should get an array with [nil]. You can see how this will break the lamda as it tries to call each_slice on nil.

[eadz]

Ok, I'm having trouble reproducing this. I'll close for now, and re-open when I can reproduce.