message: fix(core): guard against unknown ops
diff: @@ -1297,6 +1297,12 @@ export class FiberContext<E, A> implements Fiber.Runtime<E, A> {
  break
  }
  +
  + default: {
  + throw new RuntimeError(
  + `operation not supported: ${JSON.stringify(current)}`
  + )
  + }
  }
  }
  } else {
  