concurrent and thread-safe reads from netCDF / HDF5

[gauteh]

This is a tracking issue for thread-safe and concurrent reads from netCDF files. Either using a pool of file-handles, or even better concurrent read support.

older netCDF formats depend on the netCDF library, while newer depend on HDF5. the following issue will presumably be the best reference for this issue:

• Investigate where netcdf-c breaks thread safety georust/netcdf#43

hyrax has their own HDF5 implementation, which might be useful to us (maybe through rust-netcdf):

• thread-safety OPENDAP/hdf5_handler#13

[gauteh]

hidefix.