Remove hardcoded single-threaded dask scheduler for dataset combine (#…

…614)

* remove hardcoded single-threaded scheduler for dataset combine

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---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

intake_esm/source.py

@@ -252,16 +252,11 @@ def _open_dataset(self):
                         for agg in self.aggregations
                     ),
                 )
-                with dask.config.set(
-                    {'scheduler': 'single-threaded', 'array.slicing.split_large_chunks': True}
-                ):  # Use single-threaded scheduler
-                    datasets = [
-                        ds.set_coords(set(ds.variables) - set(ds.attrs[OPTIONS['vars_key']]))
-                        for ds in datasets
-                    ]
-                    self._ds = xr.combine_by_coords(
-                        datasets, **self.xarray_combine_by_coords_kwargs
-                    )
+                datasets = [
+                    ds.set_coords(set(ds.variables) - set(ds.attrs[OPTIONS['vars_key']]))
+                    for ds in datasets
+                ]
+                self._ds = xr.combine_by_coords(datasets, **self.xarray_combine_by_coords_kwargs)
 
             self._ds.attrs[OPTIONS['dataset_key']] = self.key