write vkthdf file with points only.

Development
,
1

I am trying to understand how to write a vtkhdf file.
To that end I tried to make it as simple as possible and write only points with point data. My script looks like this:

import h5py as h5
import numpy    as np
pnts = np.array([[0,0,0],
                 [1,0,0],
                 [1,1,1]])
with h5.File('points.vtkhdf', 'w') as f:
    root = f.create_group('VTKHDF', track_order=True)
    root.attrs['Version'] = (2,1)
    ascii_type = 'UnstructuredGrid'.encode('ascii')
    root.attrs.create('Type', ascii_type, dtype=h5.string_dtype('ascii', len(ascii_type)))
    
    n_steps = 1
    root.create_dataset('NumberOfPoints'         , data=[pnts.shape[0]], dtype='i8')
    root.create_dataset('NumberOfConnectivityIds', data=[0]            , dtype='i8')
    root.create_dataset('NumberOfCells'          , data=[0]            , dtype='i8')
    
    root.create_dataset('Types',        data = []  , dtype=np.uint8)
    root.create_dataset('Points',       data = pnts, dtype='f'     )
    root.create_dataset('Offsets',      data = []  , dtype='i8'    )
    root.create_dataset('Connectivity', data = []  , dtype='i8'  )

    point_data = root.create_group("PointData")
    pressure_field = (1, 2, 3, )
    point_data.create_dataset("Pressure", data=(pressure_field), dtype="f")

Paraview can open the generated “points.vtkhdf” file. Unfortunately, the points are not rendered. However, I see the points and the data in the spread sheet view.

Have I done something wrong or is it not possible to display points only with the unstructured grid vtkhdf file?