Getting hit cancels the animation. I've heard of people using amulets for that purpose.Not sure if there is any other way to get around the offscreen-damage animation delay bypass so that it becomes truly aspd based.
Trans candy is only useful if the monster's animation is significantly shorter than the character's cast animation (600ms for gene IIRC). If you see someone spamming faster than this without getting hit or abusing off-screen targets (which isn't really practical) then they're using some form of ndl.