const brand: unique symbol = Symbol('Reply'); class Reply { readonly value: T; readonly transferables: Transferable[] | undefined; // Allows TypeScript to distinguish between an actual instance of this // class versus an object that looks structurally similar. // eslint-disable-next-line no-unused-private-class-members #brand = brand; constructor( value: T, options?: { transferables?: Transferable[] | undefined; }, ) { this.value = value; this.transferables = options?.transferables; } } export default Reply;