Tag type discrimination POC

[stackoverfloweth]

Currently a tag can only have 1 possible type

const numberTab = tab<number>()

This PR introduces an alternative generic to tag that enables a single tag to have many possible sub-types.

const numberOrStringTag = tag<{
  count: number,
  name: string
}>(['count', 'name'])

Here's a real world example

type User = { id: string, name: string, email: string }
type UserAvatar = { id: string, imageUrl: string }

const userTag = tag<{
  user: User,
  avatar: UserAvatar
}>()

const userQuery = query(getUser, [userId], { tags: [userTag.user] })
const userAvatarQuery = query(getUserAvatar, [userId], { tags: [userTag.avatar] })

When invalidating queries, devs can target whatever layer they want and it will trickle down

// only invalidates the avatar queries
client.invalidateQueries(userTag.avatar)

// invalidates all 3
client.invalidateQueries(userTag)

When performing an optimistic update on a tag with multiple sub-types, the callback will require that each kind be handled

setQueryData(genericTag, {
  user: (data) => {
    expectTypeOf(data).toEqualTypeOf<User>()
    return data
  },
  avatar: (data) => {
    expectTypeOf(data).toEqualTypeOf<UserAvatar>()
    return data
  },
})