loading_cache invokes a timer that may issue asynchronous operations (queries) that would end with writing into the internal fields. We have to ensure that these operations are over before we can destroy the loading_cache object. Fixes #2624 Signed-off-by: Vlad Zolotarov <vladz@scylladb.com> Message-Id: <1501208345-3687-1-git-send-email-vladz@scylladb.com>