Realm 10.9.0

• .NETStandard 2.0

  • Fody (>= 6.6.0)
  • Microsoft.CSharp (>= 4.5.0)
  • MongoDB.Bson (>= 2.11.3)
  • Realm.Fody (>= 10.9.0)
  • Remotion.Linq (>= 2.2.0)
  • System.Buffers (>= 4.4.0)
  • System.Dynamic.Runtime (>= 4.3.0)
  • System.Runtime.CompilerServices.Unsafe (>= 4.5.3)

## 10.9.0 (2022-01-21)

### Enhancements
* Added support for a new mode of synchronization with MongoDB Realm, called ["Flexible Sync"](https://docs.mongodb.com/realm/sync/data-access-patterns/flexible-sync/). When using Flexible Sync, the client decides which queries it's interested in and asks the server for all objects matching these queries. The matching objects will be stored in a local Realm, just like before and can be queried and accessed while offline. This feature is in beta, so feedback - both positive and negative - is greatly appreciated and, as usual, we don't recommend using it for production workloads yet.
 * Added a new configuration type, called `FlexibleSyncConfiguration`. Use this type to get a `Realm` instance that uses the new synchronization mode with the server.
 * Deprecated the `SyncConfiguration` class in favor of `PartitionSyncConfiguration`. The two classes are equivalent and the new type is introduced to better contrast with `FlexibleSyncConfiguration`. The two types are equivalent and allow you to open a `Realm` instance that is using the old "Partition Sync" mode.
 * Added a new type, called `SubscriptionSet`. It is a collection, holding the various active query subscriptions that have been created for this Realm. This collection can be accessed via the `Realm.Subscriptions` property. It will be `null` for local and partition sync Realms and non-null for flexible sync Realms.

 A minimal example would look like this:
 ```csharp
 var config = new FlexibleSyncConfiguration(user);
 var realm = Realm.GetInstance(config);

 // Add a new subscription
 realm.Subscriptions.Update(() =>
 {
   var year2022 = new DateTimeOffset(2022, 1, 1);
   var saleOrders = realm.All<SaleOrder>().Where(o => o.Created > year2022);
   realm.Subscriptions.Add(saleOrders);
 });

 // Wait for the server to acknowledge the subscription and return all objects
 // matching the query
 await realm.Subscriptions.WaitForSynchronizationAsync();

 // Now we have all orders that existed on the server at the time of
 // subscribing. From now on, the server will send us updates as new
 // orders get created.
 var orderCount = realm.All<SaleOrder>().Count();
 ```
 * Multiple subscriptions can be created for queries on the same class, in which case they'll be combined with a logical `OR`. For example, if you create a subscription for all orders created in 2022 and another for all orders created by the current user, your local Realm will contain the union of the two result sets.
 * Subscriptions can be named (which makes it easier to unsubscribe) or unnamed. Adding multiple unnamed subscriptions with the same query is a no-op.
 * Modifying the set of active subscriptions is an expensive operation server-side, even if the resulting diff is not large. This is why we recommend batching subscription updates as much as possible to avoid overloading the server instance. A good practice is to declare the user subscriptions upfront - usually the first time the Realm is opened, and only update them when absolutely necessary.
 * Find more information about the API and current limitations in the [docs](https://docs.mongodb.com/realm/sdk/dotnet/fundamentals/realm-sync/).

### Compatibility
* Realm Studio: 11.0.0 or later.

### Internal
* Using Core 11.8.0.
* Release tests are executed against realm-qa instead of realm-dev. (PR [#2771](https://github.com/realm/realm-dotnet/pull/2771))