fVDB Integration ?

[ZephirFXEC]

Hey !
First of all this is a great repo, many things are interesting especially the python integration of phiflow.
You seems familiar with python, I'd love to see you integrate fVDB as i'm sure it would help for sparse computation of the phiflow 3D Smoke.
Also, have you tried making those DOPs at SOPs level within a Solver ? I'm think working with VDBs could offer some great performance improvements compared to dense volume in DOPS :)