[feature request] Instruction on how to setup compile-env for Windows

[litaws]

Hi

I have been working with extensions successfully on Linux (shipping as whl)
An end-user has asked me to provide a windows version of an extension, and I have to admit that it was not as simple as the documentation suggested here.

Can you please provide a minimal explanation or example on how to setup the compile env for this repo?
I don't mind if it is based on setuptools or cmake, as long as it does not include a non-free tool like VS-pro here

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Here are some general frame of work that will help:

• OS: >=Win10
• PyTorch version: >=1.6.0
• How you installed PyTorch (conda, pip, source): both conda and pip
• Python version: >=1.8
• CUDA version: >=10.2