Unity3D Flex plugin build guide?

Hello.

I am developing simulation program based on Nvidia FleX and Unity3D .

I checked the FleX Github source code below. but there is no guide to build Unity3D plugin.

https://github.com/NVIDIAGameWorks/FleX

I downloaded Unity3D Plugin below link.

https://assetstore.unity.com/packages/tools/physics/nvidia-flex-for-unity-1-0-beta-120425

The reason why I want to build my own version Unity plugin is I want to make some modify physics code in C++ code.

I found that these dll files in the Unity3D plugin asset directory

  1. amd_ags_x64.dll
  2. cudart64_92.dll
  3. GFSDK_Aftermath_Lib.x64.dll
  4. NvFlexExtReleaseCUDA_x64.dll
  5. NvFlexExtReleaseD3D_x64.dll
  6. NvFlexReleaseCUDA_x64.dll
  7. NvFlexReleaseD3D_x64.dll
  8. nvToolsExt64_1.dll
  9. flexUtils.dll

I understand that I can get 1~8 dll files after FleX Github source code build.

but I have no idea how to get flexUtils.dll file. Is there another GitHub repository about this?

Please help.