Since the introduction of multiplayer, it was required to launch a local server and to connect to it to play.
I now added another server implementation that replicates the behavior of a real server, but doesn’t require networking and runs within the same process.
This way most of the code is reused while allowing both modes of operation.
Sadly with this approach the simulation still runs twice. Once within the client and once within the (offline) server. This is wasteful and I’ll have to revisit it in the future.