Unity Microphone.Start() lag, how to get rid of it? - unity3d

Question

Using unity 2020.3 and the XR Plug-in (currently only oculus but will be moving to openxr i hope) and trying to start the microphone when secondary button is pushed. It works but starting the microphone causes lag. Coroutine doens't help, I tried threading which stops the lag but then can't do anything with the audioclip. This has been asked a few times over the years but no answer yet. Here's the code:
void Update()
{
foreach(var d in devices){
if (d.TryGetFeatureValue(CommonUsages.secondaryButton, out isPressed)){
if (isPressed && !wasTalking)
{
wasTalking = true;
asource.PlayOneShot(walkietalkie);
//start_recording = new Thread(startRecording);
//start_recording.Start();
startRecording();
}
else if (wasTalking && !isPressed){
finishRecording();
wasTalking = false;
}
}
private void startRecording(){
recording = Microphone.Start(null, false, 30, freq);
startRecordingTime = Time.time;
yield return null;
}
Edit: I've removed the useless coroutine. Why the -1 to my question?

Answer 1

The primary way I reckon that you could alleviate the stutter is moving this work to another thread, which is notoriously hard with Unity.
A solution to this could be using or adapting another method of recording audio like NAudio.

Answer 2

Use coroutines.
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using System.Threading;
public class TestMic : MonoBehaviour
{
[SerializeField] AudioSource self;
public int samplerate = 44100;
public int time = 10;
// Start is called before the first frame update
void Start()
{
//Debug.Log(Microphone.devices);
StartCoroutine("test");
}
IEnumerator test()
{
self.clip = Microphone.Start(null, true, time, samplerate);
self.loop = true;
self.Play();
yield return null;
}
// Update is called once per frame
void Update()
{
}
}