Sha512
class Sha512
Incremental SHA-512 (FIPS 180-4), pure Kotlin on 64-bit Long arithmetic. libtorrent pulls SHA-512 in for ed25519 (DHT mutable items, BEP 44); KiteTorrent needs it for the same reason. Validated against the FIPS test vectors.
Works on every KMP target, because Kotlin's Long is 64-bit everywhere (emulated on JS, but semantically identical).