it's already in. when u create a match, after the opponent joins there are a lot of options for the match (such as stage length, gravity on/off, di on/off,...). Two of those options are "chess timer", and "match time" or something similar. What chess timer does is take the match time in seconds instead of minutes. By default it's on and with 30s for each player (but u get an extra 4 secs each turn)