`type 'a edge````=` `{`

`child : 'a Node.t;`
`on_change : 'a ‑> unit;`
`mutable index : int Incremental_kernel__.Uopt.t;`

`}```
`type packed_edge````=`

`|` `E : 'a edge ‑> packed_edge`

``
`type 'a t````=` `{`

`f : unit ‑> 'a;`
`on_observability_change : is_now_observable:bool ‑> unit;`
`mutable children : packed_edge Incremental_kernel__.Uopt.t Incremental_kernel__.Import.Array.t;`
`mutable num_children : int;`
`mutable force_stale : bool;`
`mutable num_invalid_children : int;`
`mutable will_fire_all_callbacks : bool;`

`}```