removeFirst method
inherited
    Implementation
E removeFirst() {
  if (_head == _tail) throw StateError('No element');
  var result = _table[_head];
  _head = (_head + 1) & (_table.length - 1);
  return result;
}E removeFirst() {
  if (_head == _tail) throw StateError('No element');
  var result = _table[_head];
  _head = (_head + 1) & (_table.length - 1);
  return result;
}