[BUG] PyOpenVDB Segmentation fault when the program exits

[yuehaowang]

Environment

Operating System: Ubuntu 18.04 LTS Version: pyopenvdb 0.1.4 Other: installed by pip, python=3.7.10

Describe the bug

I write a .vdb to .npz converter following this tutorial. The program normally runs, but an error segmentation fault (core dumped) python will occur when the program exits. This problem seems not to damage the results but a little bit troublesome to me.

To Reproduce

In fact, the code below can also reproduce this problem, i.e., independent to NumPy and the file loading:

import pyopenvdb as vdb
sphere = vdb.createLevelSetSphere(radius=50, center=(1.5, 2, 3))
exit()