html_url,issue_url,id,node_id,user,created_at,updated_at,author_association,body,reactions,performed_via_github_app,issue
https://github.com/pydata/xarray/issues/4591#issuecomment-871611079,https://api.github.com/repos/pydata/xarray/issues/4591,871611079,MDEyOklzc3VlQ29tbWVudDg3MTYxMTA3OQ==,463809,2021-06-30T17:53:54Z,2021-06-30T17:53:54Z,CONTRIBUTOR,"I am trying to use `worker_client` that is opening xarrays, submitting further compute, and then saving xarrays. Perhaps somehow related to that?","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,745801652
https://github.com/pydata/xarray/issues/4591#issuecomment-870152019,https://api.github.com/repos/pydata/xarray/issues/4591,870152019,MDEyOklzc3VlQ29tbWVudDg3MDE1MjAxOQ==,463809,2021-06-29T01:10:30Z,2021-06-29T01:14:58Z,CONTRIBUTOR,"This issue appears to be back in some form, with `engine=zarr`. 

The code looks like this, using fsspec's mapper API to access Azure blob store:
```
fs = fsspec.filesystem(""az://..."")
ds = xr.open_dataset(fs.get_mapper(path), engine=""zarr"", chunks=""auto""):
   ...
```

I have not tracked down a self-contained reproducer, as it only fails for one call but not others of a similar form. Reporting it while I dig into it further, in case you have any suggestions.

```
[2021-06-29 00:44:47] [2021-06-29 00:44:47 core.py:74 CRITICAL] Failed to Serialize
[2021-06-29 00:44:47] Traceback (most recent call last):
[2021-06-29 00:44:47]   File ""/deps/envs/deps/lib/python3.7/site-packages/distributed/protocol/core.py"", line 70, in dumps
[2021-06-29 00:44:47]     frames[0] = msgpack.dumps(msg, default=_encode_default, use_bin_type=True)
[2021-06-29 00:44:47]   File ""/deps/envs/deps/lib/python3.7/site-packages/msgpack/__init__.py"", line 35, in packb
[2021-06-29 00:44:47]     return Packer(**kwargs).pack(o)
[2021-06-29 00:44:47]   File ""msgpack/_packer.pyx"", line 286, in msgpack._cmsgpack.Packer.pack
[2021-06-29 00:44:47]   File ""msgpack/_packer.pyx"", line 292, in msgpack._cmsgpack.Packer.pack
[2021-06-29 00:44:47]   File ""msgpack/_packer.pyx"", line 289, in msgpack._cmsgpack.Packer.pack
[2021-06-29 00:44:47]   File ""msgpack/_packer.pyx"", line 258, in msgpack._cmsgpack.Packer._pack
[2021-06-29 00:44:47]   File ""msgpack/_packer.pyx"", line 225, in msgpack._cmsgpack.Packer._pack
[2021-06-29 00:44:47]   File ""msgpack/_packer.pyx"", line 225, in msgpack._cmsgpack.Packer._pack
[2021-06-29 00:44:47]   File ""msgpack/_packer.pyx"", line 258, in msgpack._cmsgpack.Packer._pack
[2021-06-29 00:44:47]   File ""msgpack/_packer.pyx"", line 225, in msgpack._cmsgpack.Packer._pack
[2021-06-29 00:44:47]   File ""msgpack/_packer.pyx"", line 225, in msgpack._cmsgpack.Packer._pack
[2021-06-29 00:44:47]   File ""msgpack/_packer.pyx"", line 225, in msgpack._cmsgpack.Packer._pack
[2021-06-29 00:44:47]   File ""msgpack/_packer.pyx"", line 279, in msgpack._cmsgpack.Packer._pack
[2021-06-29 00:44:47]   File ""/deps/envs/deps/lib/python3.7/site-packages/distributed/protocol/core.py"", line 56, in _encode_default
[2021-06-29 00:44:47]     obj, serializers=serializers, on_error=on_error, context=context
[2021-06-29 00:44:47]   File ""/deps/envs/deps/lib/python3.7/site-packages/distributed/protocol/serialize.py"", line 422, in serialize_and_split
[2021-06-29 00:44:47]     header, frames = serialize(x, serializers, on_error, context)
[2021-06-29 00:44:47]   File ""/deps/envs/deps/lib/python3.7/site-packages/distributed/protocol/serialize.py"", line 256, in serialize
[2021-06-29 00:44:47]     iterate_collection=True,
[2021-06-29 00:44:47]   File ""/deps/envs/deps/lib/python3.7/site-packages/distributed/protocol/serialize.py"", line 348, in serialize
[2021-06-29 00:44:47]     raise TypeError(msg, str(x)[:10000])
[2021-06-29 00:44:47] TypeError: ('Could not serialize object of type ImplicitToExplicitIndexingAdapter.', 'ImplicitToExplicitIndexingAdapter(array=CopyOnWriteArray(array=LazilyIndexedArray(array=<xarray.backends.zarr.ZarrArrayWrapper object at 0x7f52dedbb690>, key=BasicIndexer((slice(None, None, None), slice(None, None, None))))))')
[2021-06-29 00:44:47] [2021-06-29 00:44:47 utils.py:37 ERROR] ('Could not serialize object of type ImplicitToExplicitIndexingAdapter.', 'ImplicitToExplicitIndexingAdapter(array=CopyOnWriteArray(array=LazilyIndexedArray(array=<xarray.backends.zarr.ZarrArrayWrapper object at 0x7f52dedbb690>, key=BasicIndexer((slice(None, None, None), slice(None, None, None))))))')
```

```
pip list | grep 'dask\|distributed\|xarray\|zarr\|msgpack\|adlfs'
adlfs                    0.7.7
dask                     2021.6.2
distributed              2021.6.2
msgpack                  1.0.0
xarray                   0.18.2
zarr                     2.8.3
```
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