Structs
These objects are returned when using find_by_id functionality on
DittoCollections. You can either call exec on the object to get an immediate
return value, or you can establish either a live query or a subscription,
which both work over time. A live query, established by calling
observe_local, will notify you every time there’s an update to the document
with the ID you provided in the preceding find_by_id call. A subscription,
established by calling subscribe, will act as a signal to other peers that
you would like to receive updates from them about the document with the ID
you provided in the preceding find_by_id call. Update and remove
functionality is also exposed through this object.