code: func (as *AgentState) AbleToRun(j *job.Job) (jobAction job.JobAction, errstr string) {
  	if tgt, ok := j.RequiredTarget(); ok && !as.MState.MatchID(tgt) {
  		return job.JobActionUnschedule, fmt.Sprintf("agent ID %q does not match required %q", as.MState.ID, tgt)
  	}
  
  	metadata := j.RequiredTargetMetadata()
  	if len(metadata) != 0 {
  		if !machine.HasMetadata(as.MState, metadata) {
  			return job.JobActionUnschedule, "local Machine metadata insufficient"
  		}
  	}
  
  	peers := j.Peers()
  	if len(peers) != 0 {
  		for _, peer := range peers {
  			if !as.unitScheduled(peer) {
  				return job.JobActionUnschedule, fmt.Sprintf("required peer Unit(%s) is not scheduled locally", peer)
  			}
  		}
  	}
  
  	if cExists, cJobName := as.HasConflict(j.Name, j.Conflicts()); cExists {
  		return job.JobActionUnschedule, fmt.Sprintf("found conflict with locally-scheduled Unit(%s)", cJobName)
  	}
  
  	// Handle Replace option specially for rescheduling the unit
  	if cExists, cJobName := as.hasReplace(j.Name, j.Replaces()); cExists {
  		return job.JobActionReschedule, fmt.Sprintf("found replace with locally-scheduled Unit(%s)", cJobName)
  	}
  
  	return job.JobActionSchedule, ""
  }
docs: // AbleToRun determines if an Agent can run the provided Job based on
  // the Agent's current state. A boolean indicating whether this is the
  // case or not is returned. The following criteria is used:
  //   - Agent must meet the Job's machine target requirement (if any)
  //   - Agent must have all of the Job's required metadata (if any)
  //   - Agent must have all required Peers of the Job scheduled locally (if any)
  //   - Job must not conflict with any other Units scheduled to the agent
  //   - Job must specially handle replaced units to be rescheduled