- AsyncQueryEvaluator mirrors the normal QueryEvaluator trait, except all methods return a Future wrapped value instead. - AsyncQueryEvaluator has one implementation, StandardQueryEvaluator that should cover most uses for now. It wrapps an AsyncDatabase object and a query factory. - AsyncDatabase encapsulates wrapping the blocking jdbc API within a thread pool. Currently there is one implementation that wraps a normal Database implementation, so currently it's possible to reuse the connection handling logic querulous already has built up.