Even so, some things can get screwy if the component tree sets
suspicious `key`s. Like:
```lua
{
'String 1', -- auto-assigned key = idx(1)
h(Component, { key = 1 }, {}), -- conflicting key(1)
'String 2', -- auto-assigned key = idx(3)
h(Component, { key = 2 }, {}), -- key = 2
}
```
In this example, there are two elements competing for key `1`, which
causes weird render issues.
