Using the `netcdf4` engine with `EagerReader`

[norlandrhagen]

First off, super cool library! IMO a much needed missing piece of the ecosystem.

Wondering if it's possible to use the netcdf4 engine with obspec utils and the eager reader?
From what I remember, if you use simplecache:: with fsspec, you could use the netcdf4 engine for netcdfs on cloud storage. Since the EagerReader reads the entire file, is there a similar path that would allow the netcdf4 engine to work?

[maxrjones]

EagerReader still caches the data as a buffer, and netcdf4 does not support buffered reads.

The path for using netcdf4 with obspec-utils would be to make CachingReadableStore pluggable so that the file could be cached on disk (similar to simplecache's behavior).