Update provider-scopes.md

Author: kamilmysliwiec

content/fundamentals/provider-scopes.md

@@ -197,7 +197,23 @@ export class AggregateByTenantContextIdStrategy implements ContextIdStrategy {
 
 > warning **Warning** Note this strategy is not ideal for applications operating with a large number of tenants.
 
-With this strategy in place, you can register it somewhere in your code (as it applies globally anyway), so for example, you could place it in the `main.ts` file:
+The value returned from the `attach` method instructs Nest what context identifier should be used for a given host. In this case, we specified that the `tenantSubTreeId` should be used instead of the original, auto-generated `contextId` object, when the host component (e.g., request-scoped controller) is flagged as durable (you can learn how to mark providers as durable below). Also, in this example, no payload would be registered (where payload = `REQUEST`/`CONTEXT` provider that represents the "root" - parent of the sub-tree).
+
+If you want to register the payload for a durable tree, use the following construction instead:
+
+```typescript
+return {
+  resolve: (info: HostComponentInfo) => {
+    const context = info.isTreeDurable ? tenantSubTreeId : contextId;
+    return context;
+  },
+  payload: { tenantId },
+}
+```
+
+Now whenever you inject the `REQUEST` provider (or `CONTEXT` for GraphQL applications) using the `@Inject(REQUEST)`, the `payload` object would be injected (consisting of a single property - `tenantId` in this case).
+
+Alright so with this strategy in place, you can register it somewhere in your code (as it applies globally anyway), so for example, you could place it in the `main.ts` file:
 
 ```typescript
 ContextIdFactory.apply(new AggregateByTenantContextIdStrategy());