code: function blake2b(input, key, outlen) {
      // preprocess inputs
      outlen = outlen || 64;
      input = normalizeInput(input);
      // do the math
      var ctx = blake2bInit(outlen, key);
      blake2bUpdate(ctx, input);
      return blake2bFinal(ctx);
  }
docs: Computes the BLAKE2B hash of a string or byte array, and returns a Uint8Array  Returns a n-byte Uint8Array  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