someone is there?

Hi! I have a question to apply a "stop" to this script .. to tighten ("shiftUp" button) I want the audio stops for a while (in this case the value of ShiftTime)

Here I give you the script in c # : using UnityEngine; using System.Collections;

public class prueba : MonoBehaviour {

 public AudioClip test;
 public float testvolumenMax = 1;
 public float testpitch = 1;
     public float ShiftTime = 0.8f;

 AudioSource testSource;
 Drivetrain drivetrain;
 float volumeFactor;
 int i,k;    
 
 AudioSource CreateAudioSource(AudioClip clip, bool loop, bool playImmediately, Vector3 position) {
     GameObject go = new GameObject("audio");
     go.transform.parent = transform;
     go.transform.localPosition = position;
     go.transform.localRotation = Quaternion.identity;
     go.AddComponent(typeof(AudioSource));
     go.audio.clip = clip;
     go.audio.playOnAwake = false;
     if (loop==true){
         go.audio.volume = 0;
         go.audio.loop = true;
     }
     else 
         go.audio.loop = false;
     
     if (playImmediately) go.audio.Play();
     
     return go.audio;
 }

 void Start () {

     drivetrain=GetComponent<Drivetrain>();
     testSource = CreateAudioSource(test, true, true,Vector3.zero);
 }

 void Update () {
 
     if(Input.GetButton ("Throttle")){
         if(this.drivetrain.rpm>100){
         {if (!testSource.isPlaying) testSource.Play();}
         float factor=drivetrain.rpm/drivetrain.maxRPM;
         testSource.volume = 0 + testvolumenMax*factor;
         testSource.pitch = 0.1f + testpitch*factor +0.3f;
         }
     }
     else
     {
         float factor=drivetrain.rpm/drivetrain.maxRPM;
         testSource.volume = 0.1f + testvolumenMax*factor-0.1f;
         testSource.pitch = 0.1f + testpitch*factor -0.15f;
     }
 }

}

how I can apply a stop time to audio? help me? Thanks!