Unity 3D Robot navmesh script step 3

using UnityEngine;
using System.Collections;

public class Robot : MonoBehaviour
{

    Transform target;

    public float seeDistance = 20;
    NavMeshAgent agent;
    Animation avatar;
    Transform eyes;

    // Use this for initialization
    void Start ()
    {
        target = GameObject.FindGameObjectWithTag("Player").transform;
        agent = GetComponent<NavMeshAgent> ();
        avatar = GetComponentInChildren<Animation> ();
        eyes = transform.Find ("Eyes");
        StartCoroutine( Tracking() );
    }

    IEnumerator Tracking ()
    {
        while (true) {
            yield return new WaitForSeconds(1);

            Vector3 delta = target.position - eyes.position;

            Ray ray = new Ray (eyes.position, delta);
            RaycastHit hit;

            if (Physics.Raycast (ray, out hit, seeDistance)) {

                if (hit.collider.tag == "Player")
                {
                    agent.SetDestination (target.position);
                }

            }

        }

    }



    // Update is called once per frame
    void Update ()
    {

        if (agent.velocity.magnitude > 0.1f) {
            avatar.CrossFade ("run");
        } else {
            avatar.CrossFade ("idle");
        }


    }
}