NewInMemoryJobService builds a new InMemoryJobService.

NewJob creates a new job instance.

ErrJobAlreadyExists is thrown when trying to submit a job with the same ID as one previously submitted.

ErrJobDoesNotExist is thrown when retrieving a job that does not exist.

InMemoryJobService is an implementation of JobService that only stays in memory.

Job is a reference to a running job.

Subscription receives job updates.

JobService interface defines what is needed to retrieve and persist jobs.