fieldfilebuffer.py cleanup

[VeckoTheGecko]

Remove obsolete DeferredNetcdfFileBuffer, _FileBuffer classes and unused attributes.

I also realised while doing this that fieldfilebuffer is really where a lot of the magic happens when it comes to reading in from netcdf files and coercing field input into a unified format parcels can understand. Good for me to know - I think there can be some improvements made here :)

• Chose the correct base branch (ie, swap_space_and_time_interpolation_order)

🚧 merge after #1892
mypy fixed in next PR

[erikvansebille]

Good for me to know - I think there can be some improvements made here :)

Yes, I think that the entire fieldfilebuffer.py file can be removed at some point as we transition to native xarray. But better to do it in small steps

A next step could be to also remove the support for the indices dictionary to subset the domain? This would also be felt with by xarray/dask in v4?

[VeckoTheGecko]

as we transition to native xarray. But better to do it in small steps

I think there is quite some code in this file that deals with coercing the data into a unified format. Though I think that this code should be replaced with functions that consume and produce dask arrays (or produce and consume xarray objects without triggering computation).

A next step could be to also remove the support for the indices dictionary to subset the domain? This would also be felt with by xarray/dask in v4?

Yes, I think so. I'm currently working on a few things - but I think this can do with further clearing