[zozbot234]

It looks like they're trying to map the entire "normal GPU programming model" to Rust code, including potentially things like GPU "threads" (to SIMD lanes + masked/predicated execution to account for divergence) and the execution model where a single GPU shader is launched in multiple instances with varying x, y and z indexes. In this context, it makes sense to map the GPU "warp" to a Rust thread since GPU lanes, even with partially independent program counters, still execute in lockstep much like CPU SIMD/SPMD or vector code.