Added tool to diagnose dead letters

Author: kyurkchyan

README.md

@@ -20,6 +20,7 @@ dotnet build
 | [purge-dlq](docs/purge-dlq.md)       | Purge messages from a dead letter queue                           |
 | [resubmit-dlq](docs/resubmit-dlq.md) | Resubmit messages from a dead letter queue back to the main queue |
 | [dump-dlq](docs/dump-dlq.md)         | Export DLQ messages to a JSON file                                |
+| [diagnose-dlq](docs/diagnose-dlq.md) | Diagnose DLQ messages using Application Insights telemetry        |
 
 ## Quick Start
 
@@ -41,6 +42,10 @@ dotnet run -- dump-dlq -n mynamespace.servicebus.windows.net -q myqueue -o dlq-m
 
 # Interactive mode - select which message categories to dump
 dotnet run -- dump-dlq -n mynamespace.servicebus.windows.net -q myqueue -o dlq-messages.json -i
+
+# Diagnose DLQ messages using Application Insights
+dotnet run -- diagnose-dlq -n mynamespace.servicebus.windows.net -q myqueue \
+  -a "/subscriptions/.../resourceGroups/.../providers/microsoft.insights/components/my-app-insights"
 ```
 
 ## Authentication