Using a single socket and simply passing messages to two different handlers would be much more optimal.

[kayabaNerve]

The current system halves the amount of connections we can have due to FD limits. We also have to track has live/has sync leading to issues such as #290. Finally, it's likely a bit more CPU intensive.

[kayabaNerve]

The most annoying part of this would be Transactions; we wouldn't immediately be able to tell if it's a response to a SyncRequest or just a new Transaction. It shouldn't matter in practice, especially as we can still track rejections via DataMissing, yet would complicate some internals.