The SpatialData object is not self-contained

Hello,

I am contacting you about the “not self-contained” message when saving sdata to a new location.
Here is the example:

import spatialdata as sd
from spatialdata.datasets import blobs

sdata = blobs()
sdata.write("/Volumes/One Touch/MICS/data_HE2CellType/CT_DS/test_blobs.zarr")

sdata = sd.read_zarr("/Volumes/One Touch/MICS/data_HE2CellType/CT_DS/test_blobs.zarr")

sdata.table.obs['test'] = 'test'
sdata.table.obs.head()

sdata.write("/Volumes/One Touch/MICS/data_HE2CellType/CT_DS/test_2_blobs.zarr")

And it outputs :

INFO     The SpatialData object is not self-contained (i.e. it contains some elements that are Dask-backed from    
         locations outside [/Volumes/](https://file+.vscode-resource.vscode-cdn.net/Volumes/)One Touch/MICS/data_HE2CellType/CT_DS/test_2_blobs.zarr). Please see the       
         documentation of `is_self_contained()` to understand the implications of working with SpatialData objects 
         that are not self-contained.                                                                              
INFO     The Zarr backing store has been changed from [/Volumes/](https://file+.vscode-resource.vscode-cdn.net/Volumes/)One                                                 
         Touch/MICS/data_HE2CellType/CT_DS/test_blobs.zarr the new file path: [/Volumes/](https://file+.vscode-resource.vscode-cdn.net/Volumes/)One                         
         Touch/MICS/data_HE2CellType/CT_DS/test_2_blobs.zarr

I was wondering if in this case, if I completely delete test_blobs.zarr from my disk, can I lose information in test_2_blobs.zarr or have a problem afterwards? I am having trouble understanding the implications of being “not self-contained”.

Thanks in advance for your help!

Start with the documentation and implementation of is_self_contained(), then trace the write() and read_zarr() entry points used in the example. Clarify what the warning means after writing to a new Zarr path, whether the original store is still required, and document how users can verify that the new object is self-contained.