add S3 note for .NET SDK (#521)

* add S3 note for .NET SDK

* add sentence

content/en/user-guide/integrations/sdks/dotnet/index.md

@@ -18,27 +18,51 @@ which is the preferred way of integrating the .NET SDK with LocalStack.
 Here is an example of how to create an `LambdaClient` with the endpoint set to LocalStack.
 
 ```csharp
-var lambdaClient = new AmazonLambdaClient(new AmazonLambdaConfig()
+var lambdaClient = new AmazonLambdaClient(new AmazonLambdaConfig(
     {
         ServiceURL = "http://localhost:4566"
-    });
+    }
+);
 ```
 
 If you want to specify a region and credentials when creating the client, please set them as `AuthenticationRegion` and `BasicAWSCredentials`, like in this example:
 
 ```csharp
-var lambdaClient = new AmazonLambdaClient(new BasicAWSCredentials("temp", "temp"), new AmazonLambdaConfig()
+var lambdaClient = new AmazonLambdaClient(new BasicAWSCredentials("test", "test"), new AmazonLambdaConfig(
     {
         ServiceURL = "http://localhost:4566",
         AuthenticationRegion = "eu-west-1"
-    });
+    }
+);
 ```
 
 {{< alert title="Note">}}
 Make sure you are setting the `AuthenticationRegion` and not the `RegionEndpoint`.
 Setting the `RegionEndpoint` to a constant like `RegionEndpoint.EUWest1` will override the ServiceURL, and your request will end up against AWS.
 {{< /alert >}}
 
+### S3 specific endpoint
+
+Here is another example, this time with an `S3Client` and its specific endpoint.
+
+```csharp
+var config = new AmazonS3Config({ ServiceURL = "http://s3.localhost.localstack.cloud:4566" });
+var s3client = new AmazonS3Client(config);
+```
+
+{{< alert title="Note">}}
+In case of issues resolving this DNS record, we can fallback to http://localhost:4566 in combination with the provider setting `ForcePathStyle = true`. The S3 service endpoint is slightly different from the other service endpoints, because AWS is deprecating path-style based access for hosting buckets.
+{{< /alert >}}
+
+```csharp
+var config = new AmazonS3Config(
+    {
+        ServiceURL = "http://localhost:4566",
+        ForcePathStyle = true
+    }
+);
+var s3client = new AmazonS3Client(config);
+```
 
 ## Resources