What about log_search, which is intended for permanent storage of data; could your
extension generate a log event and then use that log_id as the ls_log_id?
Maybe there could be a new type of log_type/log_action introduced, e.g.
storedata/myextension, if your extension is called MyExtension. Each extension that stores
data in this way would have its own log_action, and would generate one or more log events
as needed to reserve a log_id(s) for data storage.