RFC: Features to cull for MVP / v1

Hey all,

There are a number of feature of native API that seem like they could be
culled, at least from the MVP and v1 of WebGPU, which would help make the
API surface smaller and easier to specify.

*Transform feedback / Stream-out*: in most cases it could be replaced by
compute kernels or code in the VS that writes to a buffer. Also based on
our experience with WebGL 2, it looks extremely hard to specify this
tightly and test all corner cases.

*Sparse resources: *it is a very useful feature for high-end applications
but also somewhat new, it would be hard to specify in a reproducible manner
and the security implications are unclear. Also as far as I can tell Metal
doesn't have sparse resources.

*Tessellation: *Metal handles it very differently from D3D12 and Vulkan so
we'd need a lot of studying to make a portable version of it. That's why I
think it shouldn't be in the MVP, and maybe only as a v2 / extension on v1.

*Predicated rendering: *Metal doesn't have it.

What do you think?

Cheers,

Corentin