Performance Shift(s): `63775948`

[github-actions]

Benchmark comparison has identified performance shifts at commit 6377594 (#4617). Please review the report below and take corrective/congratulatory action as appropriate 🙂

Performance shift report

       before           after         ratio
     [45f188bb]       [63775948]
     <main~2>         <main~1>  
-      1.75±0.7μs       1000±200ns     0.57  import_iris.Iris.time_fileformats__ff_cross_references
-      0.76953125       0.30078125     0.39  save.NetcdfSave.track_addedmem_netcdf_save(600, False)

Generated by GHA run 1965956950