Constant BLAKE3_RAYON_THRESHOLD 

pub const BLAKE3_RAYON_THRESHOLD: usize = _; // 131_072usize

Threshold above which BLAKE3 hashing switches from single-thread Hasher::update to multi-thread Hasher::update_rayon. The blake3 crate documents 128 KiB as the rule-of-thumb crossover on x86_64 — below that the rayon thread-spawn overhead beats the per-byte savings, so we always take the single-thread path. Per-packet signing of normal NDN signed portions (a few hundred bytes to a few KB) never reaches this threshold; bulk content publication (multi-MB Data) does.