Assets/StreamingAssets/unity-mic-capture-worklet.js

class UnityMicCaptureProcessor extends AudioWorkletProcessor {
  process(inputs) {
    var input = inputs && inputs[0] && inputs[0][0];
    if (input && input.length) {
      this.port.postMessage(input.slice(0));
    }
    return true;
  }
}

registerProcessor("unity-mic-capture", UnityMicCaptureProcessor);