description

# removeFirst method Null safety

E removeFirst ()
override

Removes and returns the first element of this queue.

The queue must not be empty when this method is called.

## Implementation

    E removeFirst() {
      if (_head == _tail) throw IterableElementError.noElement();
      _modificationCount++;
      E result = _table[_head] as E;
      _table[_head] = null;
      _head = (_head + 1) & (_table.length - 1);
      return result;
    }