Worker AI picking jobs and moving to them using Coroutines without any Frame Update calls

Job.cs

using UnityEngine;

public class Job {
	public GameObject site;
	public float workload = 3f;
	public Job (GameObject site, float workload) {
		this.site = site;
		this.workload = workload;
	}
}

Site.cs

using UnityEngine;
using System.Collections;

public class Site : MonoBehaviour {
	bool has_job = false;
	void Start(){
		StartCoroutine (causeTrouble ());
	}

	IEnumerator causeTrouble() {
		while (true) {
			// Start off waiting a random amount of time before first job needs to be done
			float time_until_next_work_needs_to_be_done = UnityEngine.Random.Range(5f, 7f);
			yield return new WaitForSeconds (time_until_next_work_needs_to_be_done);
			// something needs to be done
			this.CreateJob();
			// wait until some other process has completed the job, then contineue
			yield return new WaitUntil(() => {return has_job == false;});
			// job is done when we come here
			// start over at the top
		}
	}

	void CreateJob () {
		has_job = true;
		GameObject indicator = transform.FindChild ("Indicator").gameObject;
		indicator.SetActive (true);
		GameObject.Find ("Worker").GetComponent<Worker> ().jobs.Push (new Job (gameObject, 1f));
	}

	public void completeJob() {
		has_job = false;
		GameObject indicator = transform.FindChild ("Indicator").gameObject;
		indicator.SetActive (false);
	}
}

Worker.cs

using UnityEngine;
using System.Collections.Generic;
using System.Collections;

public class Worker : MonoBehaviour {
	public Stack<Job> jobs;
	Job activeJob;

	void Start () {
		jobs = new Stack<Job> ();
		StartCoroutine (ai ());
	}

	IEnumerator ai () {
		while (true) { // continue for ever
			// Wait until there is a job to find
			yield return new WaitUntil (() => { return jobs.Count > 0; });
			// Grab the top job
			activeJob = jobs.Pop ();
			// Are we near enough the job to do the work?
			yield return new WaitWhile (() => {
				Vector3 distance = activeJob.site.gameObject.transform.position - gameObject.transform.position;
				if (distance.magnitude < 0.5f) {
					return false;
				}
				Vector3 move = new Vector3 (distance.x * Time.deltaTime, 0, distance.z * Time.deltaTime);
				gameObject.transform.Translate (move);
				return true;
			});
			// Simulate working by "waiting"
			yield return new WaitForSeconds (activeJob.workload); // spend workload amount of seconds working
			// Tell the site that the job is completed
			activeJob.site.GetComponent<Site> ().completeJob ();
			// Throw away active job since it was completed
			activeJob = null;
			// To back to start
		}
	}
}