Macro ic_memory_declaration 

macro_rules! ic_memory_declaration {
    (key = $stable_key:literal, ty = $label:path, id = $id:expr $(,)?) => { ... };
    (key = $stable_key:literal, label = $label:literal, id = $id:expr $(,)?) => { ... };
}

Register a MemoryManager allocation declaration during static initialization.

This macro only registers declaration metadata. It does not open stable memory. The bootstrap owner still has to collect/seal declarations, validate them against the ledger, commit the generation, and then open memory handles.