rmellis 30/11/2020

 the server is now able to determine
  whether block breaking is impacted by
 TPS. In vanilla, block breaking is
 determined by server TPS – if the TPS is
 lower, then block breaking takes longer.

 However, the client thinks block breaking
 proceeds at 20tps, so this can cause
 disagreements with the server on whether
 a block was broken or not.
This will fix this
by moving the server’s checks to use time
rather than ticks as and when needed.