pub const CHUNK_BYTES: u64 = MB_BYTES /* 1_048_576u64 */;Expand description
The payment quantum: one chunk of delivery, 1 MiB (ADR 003 §Chunk Cadence).
A protocol constant, never negotiated. No message carries it, no node advertises it, and governance does not move it — a chunk is the unit one hash-chain tick pays for, so payer and node disagreeing on it would make one released preimage worth two different amounts.
CHUNK_BYTES == MB_BYTES by identity, which is what makes a chunk cost
exactly the advertised rate_per_mb with no rounding at any rate.