Initial attempt at mountable rollback to fix 'projectile invalid' when attacking a player thats on a mini or zipline etc.
We cheat by only storing player relative positions to avoid rolling back mountables physics positions
Each client will allocate and store the last 16 ticks. 192 bytes for each mounted player, which is reused via the pool.
Retain old behaviour if not mounted hit or if the last 16 ticks aren't available