Update doc comments

lib/src/realm_class.dart

@@ -279,7 +279,10 @@ class Realm implements Finalizable {
     return object;
   }
 
-  /// TODO
+  /// Ingest an [AsymmetricObject] to the [Realm].
+  ///
+  /// Ingesting is a write only operation. The ingested object will be dead immediately
+  /// after commit, but still transferred to the backend when possible.
   void ingest<T extends AsymmetricObject>(T object) {
     final metadata = _metadata.getByType(object.runtimeType);
     final handle = _createObject(object, metadata, false);

lib/src/realm_object.dart

@@ -459,7 +459,15 @@ mixin RealmObject on RealmObjectBase implements RealmObjectMarker {}
 /// @nodoc
 mixin EmbeddedObject on RealmObjectBase implements EmbeddedObjectMarker {}
 
-/// @nodoc
+/// Base for any object that can be persisted in a [Realm], but cannot be retrieved,
+/// hence cannot be modified.
+///
+/// The benefit of using [AsymmetricObject] is that synchronization is one-way, and
+/// thus performs much better. However, they cannot be queried, or retrieved
+/// locally, which limits their use-cases greatly.
+///
+/// Use [AsymmetricObject] when you have a write-/only use case. You use it by
+/// parsing [ObjectType.asymmetricObject] to the [RealmModel] annotation.
 mixin AsymmetricObject on RealmObjectBase implements AsymmetricObjectMarker {}
 
 extension EmbeddedObjectExtension on EmbeddedObject {