An EasingFunction describes how much to modify a scalar value based on the current time, the start value, the change in value, and the duration.
The Key type is the same as string | number | undefined.
The MarginLike type is the same as Margin | number.
A number in place of a Margin object is treated as a uniform Margin with that thickness.
The BrushLike type is the same as
Brush | string | null. A string in place of a Brush object is treated as a Solid Brush of that color.