kMaterialEdges top-level property
final
    The border radii used by the various kinds of material in material design.
See also:
Implementation
final Map<MaterialType, BorderRadius> kMaterialEdges = <MaterialType, BorderRadius> {
  MaterialType.canvas: null,
  MaterialType.card: BorderRadius.circular(2.0),
  MaterialType.circle: null,
  MaterialType.button: BorderRadius.circular(2.0),
  MaterialType.transparency: null,
}