How to push external video source frame with a coroutine

AgoraPushFrame.cs

// Push frame to the remote client
    IEnumerator PushFrame(byte[] bytes, int width, int height, System.Action onFinish)
    {
        if (bytes == null || bytes.Length == 0)
        {
            Debug.LogError("Zero bytes found!!!!");
            yield break;
        }

        IRtcEngine rtc = IRtcEngine.QueryEngine();
        //if the engine is present
        if (rtc != null)
        {
            //Create a new external video frame
            ExternalVideoFrame externalVideoFrame = new ExternalVideoFrame();
            //Set the buffer type of the video frame
            externalVideoFrame.type = ExternalVideoFrame.VIDEO_BUFFER_TYPE.VIDEO_BUFFER_RAW_DATA;
            // Set the video pixel format
            //externalVideoFrame.format = ExternalVideoFrame.VIDEO_PIXEL_FORMAT.VIDEO_PIXEL_BGRA;  // V.2.9.x
            externalVideoFrame.format = ExternalVideoFrame.VIDEO_PIXEL_FORMAT.VIDEO_PIXEL_RGBA;  // V.3.x.x
       
            //apply raw data you are pulling from the rectangle you created earlier to the video frame
            externalVideoFrame.buffer = bytes;
            //Set the width of the video frame (in pixels)
            externalVideoFrame.stride = width;
            //Set the height of the video frame
            externalVideoFrame.height = height;
            //Remove pixels from the sides of the frame
            externalVideoFrame.cropLeft = 10;
            externalVideoFrame.cropTop = 10;
            externalVideoFrame.cropRight = 10;
            externalVideoFrame.cropBottom = 10;
            //Rotate the video frame (0, 90, 180, or 270)
            externalVideoFrame.rotation = 90;
            // increment i with the video timestamp
            externalVideoFrame.timestamp = i++;
            
            //Push the external video frame with the frame we just created
            int a = rtc.PushVideoFrame(externalVideoFrame);
            Debug.Log(" pushVideoFrame(" + i + ") size:" + bytes.Length + " => " + a);

        }
        yield return null;
        onFinish();
    }