apollographql/apollo-client @apollo/client@4.0.0-alpha.19 on GitHub

#12663 01512f2 Thanks @jerelmiller! - Unsubscribing from an ObservableQuery before a value has been emitted will remove the query from the tracked list of queries and will no longer be eligible for query deduplication.

#12663 01512f2 Thanks @jerelmiller! - Subscriptions created by client.subscribe() can now be restarted. Restarting a subscription will terminate the connection with the link chain and recreate the request. Restarts also work across deduplicated subscriptions so calling restart on an observable who's request is deduplicated will restart the connection for each observable.
```
const observable = client.subscribe({ query: subscription });

// Restart the connection to the link
observable.restart();
```
#12663 01512f2 Thanks @jerelmiller! - Deduplicating subscription operations is now supported. Previously it was possible to deduplicate a subscription only if the new subscription was created before a previously subscribed subscription emitted any values. As soon as a value was emitted from a subscription, new subscriptions would create new connections. Deduplication is now active for as long as a subscription connection is open (i.e. the source observable hasn't emitted a complete or error notification yet.)
To disable deduplication and force a new connection, use the queryDeduplication option in context like you would a query operation.
As a result of this change, calling the restart function returned from useSubscription will now restart the connection on deduplicated subscriptions.