GPU Direct RDMA on Windows - same question again

There are already a few posts on the subject. Yet none of them led me to find an explicit and clear answer as of March 2021.

This Comment implies that it has been added to the Quadro drivers. Yet I couldn’t find any API or documentation that explains how this is done.
I downloaded the GPUDirectForVideo SDK and docs, I haven’t found anything related to RDMA on Windows.

We are currently working with AMD cards for the sole reason they support RDMA on windows. We would very much like to try NVIDIA cards but unfortunately the documentation on this subject is very hard to find.

Can somebody answer the following questions as clear as possible:

  1. Is GPUDirectRDMA supported on windows?
  2. Is it supported by a public API? Which ones?
    (AMD DirectGMA for instance is supported with user mode API extensions for OpenCL, D3D & OpenGL)
  3. Is it supported in user mode or only kernel mode?
  4. Is it supported by Quadro cards? if not which cards exactly?
  5. Where can I find the documentation?