Function computer

computer(key: string, value: JsonValue): Promise<JsonValue>
Persist a value shared by all Programs on this computer's JournalEntry.
Parameters
- key: string
  A valid, distinctive state key, such as "example_visits".
- value: JsonValue
  JSON-serializable data; undefined, functions, BigInt, and cycles cannot be stored as values.
Returns Promise<JsonValue>
An independent JSON copy of the saved value; rejects on validation/write failure or cancellation.
Remarks
A dispatched document write can still commit after cancellation. Load/change/save is not atomic.
Example
```
await save.computer("example_visits", (load.computer("example_visits") ?? 0) + 1);
```