switchOutCurve property
The animation curve to use when transitioning a previous child out.
This curve is applied to the child when the child is faded in (or when the widget is created, for the first child). Changing switchOutCurve will not affect the curves of already-visible widgets, it only affects the curves of future children.
If child is changed while the current child is in the middle of fading in, switchInCurve will be run in reverse from that point instead of jumping to the corresponding point on switchOutCurve.
Implementation
final Curve switchOutCurve;