Use Kestrel on Windows for metrics (#6326)

* Use Kestrel on Windows for metrics

* Add comment

src/Nethermind/Nethermind.Monitoring/MonitoringService.cs

@@ -9,6 +9,7 @@
 using Nethermind.Monitoring.Config;
 using System.Net.Sockets;
 using Prometheus;
+using System.Runtime.InteropServices;
 
 namespace Nethermind.Monitoring
 {
@@ -80,8 +81,12 @@ public async Task StartAsync()
             }
             if (_exposePort is not null)
             {
-                // KestrelMetricServer intercept SIGTERM causing exitcode to be incorrect
-                IMetricServer metricServer = new MetricServer(_exposePort.Value);
+                IMetricServer metricServer = RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ?
+                    // MetricServer uses HttpListener which on Windows either needs
+                    // permissions at OS or Admin mode, whereas KestrelMetricServer doesn't need those
+                    new KestrelMetricServer(_exposePort.Value) :
+                    // KestrelMetricServer intercept SIGTERM causing exitcode to be incorrect
+                    new MetricServer(_exposePort.Value);
                 metricServer.Start();
             }
             await Task.Factory.StartNew(() => _metricsController.StartUpdating(), TaskCreationOptions.LongRunning);