Implementation: Client side


to increase accuracy, we need to filter the replies we get
"clock filter", implementing an algorithm by David Mills
basically, from 8 replies received from a peer, use the one with the lowest delay, and invalidate all older replies

bad network connection results in poor accuracy
punish peers with bad network connection - currently only based on packet loss
once punished, a peer needs to get a number of replies to us that we consider good before the peer is marked valid again and affects the total offset calculation