export const opaqueEffect = (
  description = "unmediated external effect",
): Readonly<{ readonly kind: "opaque-effect"; readonly description: string }> =>
  Object.freeze({ kind: "opaque-effect", description });
export const isOpaqueEffect = (
  value: unknown,
): value is { readonly kind: "opaque-effect"; readonly description: string } =>
  !!value && typeof value === "object" && (value as { readonly kind?: unknown }).kind === "opaque-effect";