How to setup Shader Variant Collection

Within my project, I was facing problem-related to Shader.CreateGPUProgram. Unity support person replied to use ShaderVariantCollection in an older thread that I found:

Now I don't know how to use ShaderVariantCollection within the project. I just found one useful article for this purpose: Optimizing Shader Load Time

Still, I can't find the implementation of shadervariantcollection!! If any other solution exists for me then also let me know about it because now 3 years passed after reply.