Originally I was throwing it away, but I actually thought you had asked me to do this in a previous comment.

Since putMemcache() is only called in GetMulti(), it is ignored on line 408 -- essentially all it will do is to put a memcache timeout in the logs.  That may help an end-user adjust their timeout value for what they're doing.  I don't need to log it, but I do like returning it in putMemcache() as then it's more clear what happened in GetMulti(), even if we don't do anything about it.