It is allowed to redeclare descriptors with different types in Vulkan.
MSL in general does not allow this, but for raw buffers, we can cast the
reference type at the very least.
For typed resources we are kinda hosed. Without descriptor indexing's
PARTIALLY_BOUND_BIT, descriptors must be valid if they are statically
accessed, so it would not be valid to access differently typed aliases
unless that flag is used. There might be a way to reinterpret cast
descriptors, but that seems very sketchy.
Implements support for:
- Single discrete descriptor
- Single argument buffer descriptor
- Array of argument buffer descriptors
Other cases are unimplemented for now since they are extremely painful
to unroll.
