BASIC-Kun/XBASIC - wait for VBLANK

What would be the correct way to wait for VBLANK in BASIC-Kun? I'm working on a simple game in BASIC-Kun, and need to update the screen ASAP when VBLANK occurs. Currently I'm doing it like this before updating the screen.

10 TIME=0
20 IF TIME=0 GOTO 20

This works so far, but I'm wondering if there is a better/faster/more correct way to do this?