useCast
useCast():
CastControls
The player’s casts, for an action bar’s slot or a key: cast sends
the engine’s predicted cast command with her target, and refusal and
refusalText hold why her last one did not run. Her page runs the
command on the tick she pressed, so the cast state, the cost and the
cooldowns show at once and the room’s result settles them. The clip
plays as her cast starts, once per cast, from the press on or as the
room’s cast arrives, and a refusal stops it. Two calls on one page share
the work: each cast plays one clip.