Update bgp-diagnostics.md

Author: stegag

articles/vpn-gateway/bgp-diagnostics.md

@@ -119,6 +119,10 @@ Use **Get-AzVirtualNetworkGatewayAdvertisedRoute** to view all the routes that t
 Get-AzVirtualNetworkGatewayAdvertisedRoute -VirtualNetworkGatewayName gatewayName -ResourceGroupName resourceGroupName -Peer 10.0.0.254
 ```
 
+## Rest API
+
+You can also use the GetBgpPeerStatus [Rest API call](https://learn.microsoft.com/rest/api/network-gateway/virtual-network-gateways/get-bgp-peer-status) to retrieve the information. Note that this is an Async operation and will return a 202 status code. You will need to fetch the results via and additional GET call. For more information see [Azure-AsyncOperation request and response](./azure-resource-manager/management/async-operations.md#azure-asyncoperation-request-and-response)
+
 ## Next steps
 
 For more information about BGP, see [Configure BGP for VPN Gateway](bgp-howto.md).