WebGL added entry points which take an ArrayBuffer + srcOffset (offset into the AB). This was necessary so that applications don't have to constantly create ArrayBufferView garbage for every call. Especially important for WASM where the source AB is WASM memory - so always requires an offset.

Could be a dictionary that has AB+offset, I suppose, but likely creates just as much garbage.

No one likes that we have to design around GC, but it's how it is.