# ListQueue<E> constructor

ListQueue<E>([int initialCapacity ])

Create an empty queue.

If `initialCapacity` is given, prepare the queue for at least that many elements.

## Implementation

    ListQueue([int initialCapacity])
        : _head = 0,
          _tail = 0 {
      if (initialCapacity == null || initialCapacity < _INITIAL_CAPACITY) {
        initialCapacity = _INITIAL_CAPACITY;
      } else if (!_isPowerOf2(initialCapacity)) {
        initialCapacity = _nextPowerOf2(initialCapacity);
      }
      assert(_isPowerOf2(initialCapacity));
      _table = new List<E>(initialCapacity);
    }