The last data reference committed to this object's GPU buffers
(undefined when never committed or demoted). Used for the no-op
identity comparison — reference equality is sufficient because the
memoized loaders return the same object for unchanged data.
The last data reference committed to this object's GPU buffers (
undefinedwhen never committed or demoted). Used for the no-op identity comparison — reference equality is sufficient because the memoized loaders return the same object for unchanged data.