XIOS3 missing value

[mo-marqh]

Are there any linked Issues or Pull Requests?

No response

Brief description

A specific feature was put into XIOS2 to adapt how _FillValue is written out:
https://gitlab.in2p3.fr/ipsl/projets/xios-projects/xios/-/commit/613dc4912761a20ae0d131c3717e6a98b90af2d7

but this is not part of the XIOS3 feature set.
https://gitlab.in2p3.fr/ipsl/projets/xios-projects/xios/-/blob/main/src/io/nc4_data_output.cpp?ref_type=heads

Evaluate the test failures due to differing _FillValues on output and decide whether to:

• re-propose the previous XIOS2 to XIOS3
• propose an alternative feature for XIOS3 to better meet our output missing data requirement

Further details of the issue.

No response