Using GhostOffsets in Xdmf files

[jannisteunissen]

I would like to use Visit's Xdmf reader to read in multiple blocks. These blocks have so-called ghost zones. In the database reader there appears to be support for this, since it reads the "BaseIndex and GhostOffsets properties" in avtXdmfFileFormat::GetMesh, see https://github.com/visit-dav/visit/blob/develop/src/databases/Xdmf/avtXdmfFileFormat.C

However, I cannot get this functionality to work with a simple example. For example, consider the following 4x4 mesh:

<?xml version="1.0" encoding="US-ASCII"?>
<!DOCTYPE Xdmf SYSTEM "Xdmf.dtd" []>
<Xdmf Version="2.0">
  <Domain>
    <Grid Name="Mesh" GridType="Collection">
      <Grid Name="MeshBlock1" GridType="Uniform">
        <Topology TopologyType="2DRectMesh" Dimensions="5 5"/>
        <Geometry GeometryType="ORIGIN_DXDY">
          <DataItem Dimensions="2">
            0.0 0.0
          </DataItem>
          <DataItem Dimensions="2">
            1.0 1.0
          </DataItem>
        </Geometry>
      </Grid>
    </Grid>
  </Domain>
</Xdmf>

I have tried to include ghost zones in this example, by adding

        <Information Name="GhostOffsets" Value="1 1 1 1"/>

below the topology definition, so that the resulting file is:

<?xml version="1.0" encoding="US-ASCII"?>
<!DOCTYPE Xdmf SYSTEM "Xdmf.dtd" []>
<Xdmf Version="2.0">
  <Domain>
    <Grid Name="Mesh" GridType="Collection">
      <Grid Name="MeshBlock1" GridType="Uniform">
        <Topology TopologyType="2DRectMesh" Dimensions="5 5"/>
        <Information Name="GhostOffsets" Value="1 1 1 1"/>
        <Geometry GeometryType="ORIGIN_DXDY">
          <DataItem Dimensions="2">
            0.0 0.0
          </DataItem>
          <DataItem Dimensions="2">
            1.0 1.0
          </DataItem>
        </Geometry>
      </Grid>
    </Grid>
  </Domain>
</Xdmf>

However, the only thing that I get is an error: The Mesh plot of variable "Mesh" yielded no data. This error is also present when I change the GhostOffsets to "0 0 0 0" or "0 0 0 0 0 0" (since Visit appears to interpret 2D collections as 3D, see #19437). So my question is, how to correctly specify GhostOffsets in this example?