code: public boolean add(JobStatus jobStatus) {
          boolean replaced = mJobSet.remove(jobStatus);
          mJobSet.add(jobStatus);
          if (!jobStatus.isPersisted()) {
              markForBootSession(jobStatus);
          }
          maybeWriteStatusToDiskAsync();
          return replaced;
      }
docs: Add a job to the master list, persisting it if necessary. If the JobStatus already exists,
  it will be replaced.
  
  @param jobStatus Job to add.
  @return Whether or not an equivalent JobStatus was replaced by this operation.