allback will be tested.
    checkTransform('abc012', 'abc012');
    checkTransform([100, 101, 102, 51, 52, 53], 'def345');
    checkTransform(createArrayBuffer([103, 104, 105, 54, 55, 56]), 'ghi678');
    checkTransform(new Uint8Array([106, 107, 108, 57, 58, 59]), 'jkl9:;');

    if (typeof TextDecoder === 'undefined') {
      // The browser doesn't support TextDecoder, so we have already checked
      // the jszip fallback.
      return;
    }

    // The browser supports TextDecoder, so we now check the j