This protects us from the edge case of potentially stale
memcache data due to a DeadlineExceededExeption, or possibly
from MemcacheServiceException. If memcache gets stale and
misses a write that went to Datastore, it will catch up in
at most one hour.
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=116174023