reserve
Reserves one complete portable generation before the caller allocates any native resource.
The copied layer extents bound both resource count and each allocation's shape; the adapter must allocate them in this order. An empty extent list is valid and still requires sealing after any attempted initialization. Full quotas fail before allocation or output, without changing the previous presentation or native Canvas's independent fallback policy.
Return
an unsealed token whose permit survives every incomplete release path.
Parameters
stable identity returned by this device.
exact positive physical layer sizes, copied without retaining the caller's collection.
Throws
for nonpositive extents.
when a layer's pixel count or the generation identity cannot be represented.
for foreign identities, exhausted quotas, reentry, or terminal/off-thread access.