update static method

Implementation

static bool update([time]) {
  if (_tweens.isEmpty) return false;

  int i = 0, l = _tweens.length;
  time = time ?? DateTime.now().millisecondsSinceEpoch;

  while (i < l) {
    if (_tweens[i]._update(time)) {
      i++;
    } else {
      _tweens.removeAt(i);
      l--;
    }
  }

  return true;
}