It is probably not a good idea for hangfire, because every job has it's own id and generated by hangifre itself, so you will have to find out all child jobs (in case of job retries and so on) to correctly pause (actually delete) them.
However you can follow this tip:
Let's say we want to pause job with Id = '12345' (or even with specific argument). We can save if to special table in our DB, called 'paused'
We also should create a custom IServerFilter where we must implement the some logic to check if the job is in 'paused' table. If so, then just skip it. So as you can guess the resuming job it is just removing this job from 'paused' table