[FEATURE REQUEST] Implement Stream priorities

I think I'm able to say that stream priority isn't implemented in pycuda right now.

Although Cuda gives the possibility to allocate priorities to Streams, as pointed out here : 
https://docs.nvidia.com/cuda/cuda-c-programming-guide/index.html#stream-priorities

Will you please think about adding this feature whenever you can ? Or do you know of any workaround ?

Cordially