Currently, there is no way that I know of to force the day time to update on the client. The day time does update once every twenty ticks, but for that to be spend up to once per frame @ 60 FPS, the server would need to be /tick warping at least 1,200 ticks per second, which is infeasible in almost all cases with current hardware.

One reason for such fast updates is when the daytime is simulated speeding up, such as what happens in the opening ceremony of some of the MCC championships. Another reason is when you want to create a "timelapse" but live (for example slow decay or construction of something with the time speeding up to emphasize that effect)

The new function would be something like day_time(new_time, update=false), where setting update to true would send time update packets to clients immediately instead of waiting up to 20 ticks.