code: function blake2bHex(input, key, outlen) {
      var output = blake2b(input, key, outlen);
      return toHex(output);
  }
docs: Computes the BLAKE2B hash of a string or byte array  Returns an n-byte hash in hex, all lowercase  Parameters: - input - the input bytes, as a string, Buffer, or Uint8Array - key - optional key Uint8Array, up to 64 bytes - outlen - optional output length in bytes, default 64