easeOutExpo constant
A cubic animation curve that starts quickly and ends slowly. This curve is a flipped version of Curves.easeInExpo. Using this curve can give your animations extra flare, but a longer duration may need to be used to compensate for the steepness of the curve.
Derived from Robert Penner’s easing functions.
Implementation
static const Cubic easeOutExpo = Cubic(0.19, 1.0, 0.22, 1.0);