implement RecyclerItem for https://medium.com/@tonny/recyclerview-2020-when-recyclerview-meets-data-binding-616ca5c2147d

User.kt

data class User(
    ...
) : RecyclerItem {
    override val layoutId: Int
        get() = R.layout.list_item_user

    override val variableId: Int
        get() = BR.user

    override val dataToBind: Any
        get() = this

    override val id: Int
        get() = this.id
}