How to use the @vue/reactivity.TriggerOpTypes.DELETE function in @vue/reactivity

obj.foo++
    await nextTick()
    expect(onTrigger).toHaveBeenCalledTimes(1)
    expect(events[0]).toMatchObject({
      type: TriggerOpTypes.SET,
      key: 'foo',
      oldValue: 1,
      newValue: 2
    })

    delete obj.bar
    await nextTick()
    expect(onTrigger).toHaveBeenCalledTimes(2)
    expect(events[1]).toMatchObject({
      type: TriggerOpTypes.DELETE,
      key: 'bar',
      oldValue: 2
    })
    ;(obj as any).baz = 3
    await nextTick()
    expect(onTrigger).toHaveBeenCalledTimes(3)
    expect(events[2]).toMatchObject({
      type: TriggerOpTypes.ADD,
      key: 'baz',
      newValue: 3
    })
  })
})

await nextTick()
    expect(dummy).toBe(2)
    expect(onTrigger).toHaveBeenCalledTimes(1)
    expect(events[0]).toMatchObject({
      type: TriggerOpTypes.SET,
      key: 'foo',
      oldValue: 1,
      newValue: 2
    })

    delete obj.foo
    await nextTick()
    expect(dummy).toBeUndefined()
    expect(onTrigger).toHaveBeenCalledTimes(2)
    expect(events[1]).toMatchObject({
      type: TriggerOpTypes.DELETE,
      key: 'foo',
      oldValue: 2
    })
  })
})