* Initial work on persistent queues
* Update index for event ID and server name
* Put things into database (postgres for now)
* Duplicate postgres code into sqlite for now just to stop build errors, will fix SQLite soon
* Fix table name
* Fix index
* Fix table name
* Use RETURNING because LastInsertID is not supported by postgres
* Use functions
* Marshal headered event
* Don't error on now rows
* Don't block if there are PDUs waiting
* Try to tidy up JSON
* Debug logging
* Fix query, use transactions in postgres
* Clean up
* Rehydrate more opportunistically
* Fix SQLite
* remove unused types
* Review comments
* Shuffle things around a bit
* Clean up transaction properly
* Don't send empty transactions
* Reduce unnecessary retries
* Count PDUs to make more resilient
* Don't stop when there is work to be done
* Try to limit wakeups
* well this is tedious
* Fix race in incomplete transactions
* Thread safety on transaction ID/count
