Currently the `job_resource` struct is opaque and unavailable to the public header file. I'm trying to create a slurm promtheus exporter [here](https://github.com/rivosinc/prometheus-slurm-exporter) and use the c plugin api instead of scraping the cmd line or json outputs as the c plugin is more stable and performant. For that, I need all the resource info I can get. This opaque struct (https://github.com/SchedMD/slurm/blob/master/src/common/job_resources.h#L106-L128) also doesn't provide a set of public methods to extract the required resources. If either of those options could be provided I would be greatful. As it stands I'm unsure as to why this struct would be made opaque in the first place. Perhaps I'm missing something.