You deployed an Azure App Service web app, enabled Always On and the Application Insights site extension, then deployed a code update that produced many failed requests and exceptions. Which Application Insights tool lets you validate performance and failure counts in near real time?

Live Metrics Stream provides near real-time telemetry from your running application, including request rates, failures, and exceptions, with a latency of about one second. This makes it ideal for immediately observing the impact of a new deployment. Profiler helps diagnose performance bottlenecks in your code, but it's not for real-time monitoring of general failures. Smart Detection automatically warns you of potential performance problems or failures, but it's an alert system, not a real-time viewing tool. Application Map visualizes the components of your distributed application and their interactions, useful for understanding dependencies, but not for immediate failure counts. Snapshot Debugger captures a snapshot of your application's state when an exception occurs, useful for post-mortem debugging, not live monitoring.