* Offset updates take place using TransactionWriter
* Refactor TransactionWriter in current state server
* Refactor TransactionWriter in federation sender
* Refactor TransactionWriter in key server
* Refactor TransactionWriter in media API
* Refactor TransactionWriter in server key API
* Refactor TransactionWriter in sync API
* Refactor TransactionWriter in user API
* Fix deadlocking Sync API tests
* Un-deadlock device database
* Fix appservice API
* Rename TransactionWriters to Writers
* Move writers up a layer in sync API
* Document sqlutil.Writer interface
* Add note to Writer documentation
* Updated TransactionWriters, moved locks in roomserver, various other tweaks
* Fix redaction deadlocks
* Fix lint issue
* Rename SQLiteTransactionWriter to ExclusiveTransactionWriter
* Fix us not sending transactions through in latest events updater
* Deduplicate FS database, add some EDU persistence groundwork
* Extend TransactionWriter to use optional existing transaction, use that for FS SQLite database writes
* Fix build due to bad keyserver import
* Working EDU persistence
* gocyclo, unsurprisingly
* Remove unused
* Update copyright notices
* 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
