Function stable_cell_payload_length 

pub fn stable_cell_payload_length<M: Memory>(
    memory: &M,
    maximum: usize,
) -> Result<usize, StableCellPayloadError>

Validate a stable-cell envelope and return its payload length.

Reject empty/foreign memory, unsupported layouts, lengths beyond the backing extent, and lengths above the caller’s maximum. No payload is allocated or read, and memory is never written or grown. This does not validate the value’s codec or schema. The ledger reader retains its separate recovery ceiling.

Panics

Propagates backing size/read failures.