Add section for customer serialization

Author: PramodValavala-MSFT

articles/cosmos-db/sql/sql-api-dotnet-v3sdk-samples.md

@@ -6,7 +6,7 @@ ms.author: esarroyo
 ms.service: cosmos-db
 ms.subservice: cosmosdb-sql
 ms.topic: sample
-ms.date: 08/26/2021
+ms.date: 02/23/2022
 ms.custom: devx-track-dotnet
 
 ---
@@ -129,6 +129,10 @@ The [RunDemoAsync](https://github.com/Azure/azure-cosmos-dotnet-v3/blob/master/M
 | [Execute a stored procedure](https://github.com/Azure/azure-cosmos-dotnet-v3/blob/master/Microsoft.Azure.Cosmos.Samples/Usage/ServerSideScripts/Program.cs#L135) |[Scripts.ExecuteStoredProcedureAsync](/dotnet/api/microsoft.azure.cosmos.scripts.scripts.executestoredprocedureasync) |
 | [Delete a stored procedure](https://github.com/Azure/azure-cosmos-dotnet-v3/blob/master/Microsoft.Azure.Cosmos.Samples/Usage/ServerSideScripts/Program.cs#L351) |[Scripts.DeleteStoredProcedureAsync](/dotnet/api/microsoft.azure.cosmos.scripts.scripts.deletestoredprocedureasync) |
 
+## Custom Serialization
+
+The [SystemTextJson](https://github.com/Azure/azure-cosmos-dotnet-v3/blob/master/Microsoft.Azure.Cosmos.Samples/Usage/SystemTextJson/Program.cs) sample project shows how to use a custom serializer when initializing a new `CosmosClient` object. The sample also includes [a custom `CosmosSerializer` class](https://github.com/Azure/azure-cosmos-dotnet-v3/blob/master/Microsoft.Azure.Cosmos.Samples/Usage/SystemTextJson/CosmosSystemTextJsonSerializer.cs) which leverages `System.Text.Json` for serialization and deserialization.
+
 ## Next steps
 
 Trying to do capacity planning for a migration to Azure Cosmos DB? You can use information about your existing database cluster for capacity planning.