Are _MeshIndexSets still successfully lazy pointers to original arrays?

[trexfeathers]

The construction of connectivity and coordinate arrays has gone through many iterations. I am no longer 100% clear whether it delivers on the original promise of a Dask array that updates when the arrays on the original connectivities and coordinates get updated.

Suspect #7209 may have influenced things?

my_mesh = MeshXY(...)
my_index_set = _MeshIndexSet(my_mesh, ...)
assert my_index_set.node_coords[0].points == 100.0

# This is fine
my_mesh.node_coords.points[0] = 200.0
assert my_index_set.node_coords[0].points[0] == 200.0

# This is not
my_coord = my_index_set.node_coords[0]
my_mesh.node_coords.points[0] = 300.0
assert my_coord.points[0] == 300.0