Resolves the per-buffer byte arrays a Subtree needs. A buffer with no
uri is the file's internal binary chunk; an external one (uri set) is fetched
through fetchExternal (the caller resolves the URI against the subtree's base).
No declared buffers → bufferViews reference the internal binary as buffer 0.
Resolves the per-buffer byte arrays a Subtree needs. A buffer with no
uriis the file's internal binary chunk; an external one (uriset) is fetched throughfetchExternal(the caller resolves the URI against the subtree's base). No declared buffers → bufferViews reference the internal binary as buffer 0.