lerp method
Linearly interpolate between two MessageListView themes.
All the properties must be non-null.
Implementation
MessageListViewThemeData lerp(
MessageListViewThemeData a,
MessageListViewThemeData b,
double t,
) =>
MessageListViewThemeData(
backgroundColor: Color.lerp(a.backgroundColor, b.backgroundColor, t),
backgroundImage: t < 0.5 ? a.backgroundImage : b.backgroundImage,
);