Interface b2SurfaceMaterial

interface b2SurfaceMaterial {
    customColor: number;
    friction: number;
    restitution: number;
    rollingResistance: number;
    tangentSpeed: number;
    userMaterialId: bigint;
    clone(): this;
    delete(): void;
    deleteLater(): this;
    isAliasOf(other: ClassHandle): boolean;
    isDeleted(): boolean;
    [key: number]: () => void;
}