To dos

Most functionality beyond simple store/load. :) pack, replication, etc.
Something to check for invalid data.
Lock/vote timeouts. (Probably using the timer crate.)
Better unmarshalling errors. tpc_begin error -> client waiting for vote. Basically, errors in async methods on server should disconnect.
server logging
Client gets invalis transaction error after reconnecting while waiting for vote response. It should already have aborted.