The angular compactness of the children on the wheel.
This denotes a ratio of the number of children on the wheel vs the number of children that would fit on a flat list of equivalent size, assuming diameterRatio of 1.
For instance, if this RenderListWheelViewport has a height of 100px and itemExtent is 20px, 5 items would fit on an equivalent flat list. With a squeeze of 1, 5 items would also be shown in the RenderListWheelViewport. With a squeeze of 2, 10 items would be shown in the RenderListWheelViewport.
Changing this value will change the number of children built and shown inside the wheel.
Must not be null and must be positive.
1.45 fo visually mimic iOS.
final double squeeze