O(1). Returns queue of no elements.

O(1), amortized. Returns the first element.

O(1). Returns true if the queue has no elements.

O(1). Returns the count of elements.

O(1). Returns a queue of the seq.

O(1). Returns queue reversed.

O(1), amortized. Returns a new queue with the element added to the end.

O(1), amortized. Returns a new queue of the elements trailing the first element.

O(1), amortized. Returns option first element.

O(1), amortized. Returns option queue of the elements trailing the first element.

O(1), amortized. Returns option first element and tail.

O(1), amortized. Returns the first element and tail.