# poll method

E? poll()

Retrieves and removes the head of this queue.

Returns null if this queue is empty.

Example:

    final queue = Queue<String>();
    queue.offer('hello');
    final polled = queue.poll(); // 'hello'
    final empty = queue.poll(); // null

## Implementation

    E? poll() {
      if (_elements.isEmpty) {
        return null;
      }
      return _elements.removeAt(0);
    }