bug: flopy.utils.cvfdutil.shapefile_to_cvfd gets stuck

[oscarfasanchez]

Describe the bug
A clear and concise description of what the bug is:
flopy.utils.cvfdutil.shapefile_to_cvfd gets stuck (never finishes) when skip_hanging_node_check = True
when some voronoi grids are used, this is related to the issue #2321

To Reproduce
Steps to reproduce the behavior:
use
shp=
gdf_voro.zip

flopy.utils.cvfdutil.shapefile_to_cvfd(shp, skip_hanging_node_check = True)
or
flopy.utils.cvfdutil.to_cvfd( ... , skip_hanging_node_check = True)

Expected behavior
it should finish after a few seconds

Thank you for your time

[wpbonelli]

I think this fails due to artifacts in your grid definition in particular duplicate vertices close to other vertices.

The check should succeed for clean Voronoi grids, although I think it's meant mainly for quad-refinement.

#2688 improves the docstrings and aims to abort the check when it hangs.