After the span, offset and align discussion I wonder if the right idea is to just remove offset.

Proposal

We spec the alignment and span of each type that can be put in a buffer, this is partially done already with the Alignment table in the spec. So, we spec something along the lines of:

| type | align | span |
| vec2 | 8     | 8    |
| vec3 | 16    | 16   |
| vec4 | 16    | 16   |
| f32   | 4    | 4    |
| ... |

We can then, if desired, update the various compilers to dump out the offsets for a given struct to make matching up to the API side easier (would this be useful as a reflection API?)

Future

If, in the future, we want packed types, we add a [[packed]] decoration to structs, at that point, all members of the struct would be tightly packed they'd all have a span of their exact type size (so vec3 spans 12) and there would be no padding injected between them.