Redis::get() returns false when a key does not exist.
igbinary_unserialize(false) produces a PHP warning and returns false,
which can cause unexpected behavior or fatal errors on the streaming
hot path.
All 5 call sites now check for false before deserializing:
- ConnectionTracker::getConnection()
- ConnectionTracker::closeConnection() (internal lookup)
- ConnectionLimiter::closeConnection()
- reseller_api_actions.php (line_activity kill)
- UsersCronJob (mGet bulk deserialize via array_map)