Stops the pool's workers (if the pool is this object's own). This object's unfinished builds reject, on a shared pool too (a build already running on a shared pool finishes there and its result is dropped).
Builds geometry's tree in a worker. Takes computeBoundsTree's
options (three-mesh-bvh's), checked before the build starts; onProgress
gets 0 when the build is asked for and 1 when it is back. Doesn't set
geometry.boundsTree.
The tree is built from the positions as they are when generate is
called: edits made while it builds leave it stale (raycasts use three's
own until boundsTree.refit()).
True while a
generateis unfinished.