伪随机函数(又名的散列函数)

Implements siphash 2-4 specialized for a 4 u64 array key and a u64 nonce

    /// Generates a node in the cuckoo graph generated from our seed. A node is
    /// simply materialized as a u64 from a nonce and an offset (generally 0 or
    /// 1).

siphash24