A cubic animation curve that starts slowly, speeds up, and then ends slowly.
Since this curve is arrived at with an exponential function, the midpoint is exceptionally steep. Extra consideration should be taken when designing an animation using this.
Compared to Curves.easeInOutQuint, this curve is slightly steeper.
Derived from Robert Penner’s easing functions.
static const Cubic easeInOutExpo = Cubic(1.0, 0.0, 0.0, 1.0);