how many times per second does blockland send data from server to client or vice versa? 60? more than that?
As they said before, that is for schedules.
What you ask, though, is more about how low the latency between client and server is. It also is about how many times the engine updates per second. As mentioned previously, that is where schedules comes in, as that gives a hint of how many times that happens at most. Therefore, packages between the server and client will happens asynchronously, but at best it will be 60 times a second.