testXorUint8Array() {
    if (globalThis.Uint8Array === undefined) {
      // Uint8Array not supported.
      return;
    }

    assertElementsEquals(
        [20, 83, 96, 66],
        crypt.xorByteArray(
            new Uint8Array([202, 254, 222, 173]),
            new Uint8Array([222, 173, 190, 239])));
  }
Same as testXorByteArray but with Uint8Array instead of Array<number>.