Steps

• Diagnose
• Write up
• Discuss with Iris devs to decide on next steps to fix

Possible causes:

• Once per file
• Once per NetCDF variable
• Once per Dask worker
  E.g. Some work happens within a NetCDFDataProxy, and there is one of these per chunk
• Use of generators

Finding examples

• Try loading some of the iris-test-data files
• Read the Iris CI output (example)
• Get a list of warnings generated by Iris, then check them with users for familiar 'culprits'