eye tracking Unity got crashed while getting eye tracking data by VIVE OpenXR Plugin

[KikyoNanakusa]

My Unity got crashed when I ran the script below. 

using UnityEngine;
using VIVE.OpenXR;
using VIVE.OpenXR.EyeTracker;

public class EyeTracker : MonoBehaviour
{
    void Update()
    {
        XrSingleEyeGazeDataHTC[] gazeData;
        XR_HTC_eye_tracker.Interop.GetEyeGazeData(out gazeData);

        if (gazeData != null)
        {
            XrSingleEyeGazeDataHTC leftGaze = gazeData[(int)XrEyePositionHTC.XR_EYE_POSITION_LEFT_HTC];
            if (leftGaze.isValid)
            {
                Debug.Log($"Left Eye Gaze Position: {leftGaze.gazePose.position.ToUnityVector()}");
                Debug.Log($"Left Eye Gaze Orientation: {leftGaze.gazePose.orientation.ToUnityQuaternion()}");
            }
            else
            {
                Debug.Log("Left Eye Gaze Data is Invalid.");
            }

            XrSingleEyeGazeDataHTC rightGaze = gazeData[(int)XrEyePositionHTC.XR_EYE_POSITION_RIGHT_HTC];
            if (rightGaze.isValid)
            {
                Debug.Log($"Right Eye Gaze Position: {rightGaze.gazePose.position.ToUnityVector()}");
                Debug.Log($"Right Eye Gaze Orientation: {rightGaze.gazePose.orientation.ToUnityQuaternion()}");
            }
            else
            {
                Debug.Log("Right Eye Gaze Data is Invalid.");
            }
        }

        XrSingleEyeGeometricDataHTC[] geometricData;
        XR_HTC_eye_tracker.Interop.GetEyeGeometricData(out geometricData);

        if (geometricData != null)
        {
            XrSingleEyeGeometricDataHTC leftGeom = geometricData[(int)XrEyePositionHTC.XR_EYE_POSITION_LEFT_HTC];
            if (leftGeom.isValid)
            {
                Debug.Log($"Left Eye Openness: {leftGeom.eyeOpenness}");
                Debug.Log($"Left Eye Squeeze: {leftGeom.eyeSqueeze}");
                Debug.Log($"Left Eye Wide: {leftGeom.eyeWide}");
            }
            else
            {
                Debug.Log("Left Eye Geometric Data is Invalid.");
            }

            XrSingleEyeGeometricDataHTC rightGeom = geometricData[(int)XrEyePositionHTC.XR_EYE_POSITION_RIGHT_HTC];
            if (rightGeom.isValid)
            {
                Debug.Log($"Right Eye Openness: {rightGeom.eyeOpenness}");
                Debug.Log($"Right Eye Squeeze: {rightGeom.eyeSqueeze}");
                Debug.Log($"Right Eye Wide: {rightGeom.eyeWide}");
            }
            else
            {
                Debug.Log("Right Eye Geometric Data is Invalid.");
            }
        }

        XrSingleEyePupilDataHTC[] pupilData;
        XR_HTC_eye_tracker.Interop.GetEyePupilData(out pupilData);

        if (pupilData != null)
        {
            XrSingleEyePupilDataHTC leftPupil = pupilData[(int)XrEyePositionHTC.XR_EYE_POSITION_LEFT_HTC];
            if (leftPupil.isDiameterValid)
            {
                Debug.Log($"Left Eye Pupil Diameter: {leftPupil.pupilDiameter}");
            }
            else
            {
                Debug.Log("Left Eye Pupil Diameter is Invalid.");
            }

            if (leftPupil.isPositionValid)
            {
                Debug.Log($"Left Eye Pupil Position: {leftPupil.pupilPosition}");
            }
            else
            {
                Debug.Log("Left Eye Pupil Position is Invalid.");
            }

            XrSingleEyePupilDataHTC rightPupil = pupilData[(int)XrEyePositionHTC.XR_EYE_POSITION_RIGHT_HTC];
            if (rightPupil.isDiameterValid)
            {
                Debug.Log($"Right Eye Pupil Diameter: {rightPupil.pupilDiameter}");
            }
            else
            {
                Debug.Log("Right Eye Pupil Diameter is Invalid.");
            }

            if (rightPupil.isPositionValid)
            {
                Debug.Log($"Right Eye Pupil Position: {rightPupil.pupilPosition}");
            }
            else
            {
                Debug.Log("Right Eye Pupil Position is Invalid.");
            }
        }
    }
}

Then I tried sample scene, that contain the script like above. However my unity crashed again. 

My environment is this

- Unity 2021.3.9f1

- VIVE OpenXR Plugin Version 2.4.2

- HMD: VIVE Pro eye

Because of  this situation, I googled about old versions of eyes and facial tracker SDK, but it seems HTC removed all sources. 
Like the URL below

- https://developer.vive.com/resources/vive-sense/eye-and-facial-tracking-sdk/download/latest/

Is there any way to track eye gaze data?
If anyone has the official URL that provide older versions of SDK ( it means non-OpenXR SDK) or know the method to do eye tracking by using current SDK (VIVE OpenXR Plugin), please teach me how.