hide jellyfin timing stats by default; enable with env var (#2756)

CHANGELOG.md

@@ -40,6 +40,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
   - `ETV_SLOW_API_MS` - milliseconds threshold for logging slow API calls (at DEBUG level)
     - This is currently limited to *Jellyfin*
   - `ETV_JF_PAGE_SIZE` - page size for library scan API calls to Jellyfin; default value is 10
+  - `ETV_JF_ENABLE_STATS` - enables logging timing information related to Jellyfin show library scans
 - Add `Select All` button to media pages by @Erotemic
 
 ### Fixed

ErsatzTV.Core/SystemEnvironment.cs

@@ -56,6 +56,8 @@ public class SystemEnvironment
         }
 
         JellyfinPageSize = jellyfinPageSize;
+
+        JellyfinEnableStats = !string.IsNullOrWhiteSpace(Environment.GetEnvironmentVariable("ETV_JF_ENABLE_STATS"));
     }
 
     public static string BaseUrl { get; }
@@ -68,4 +70,5 @@ public class SystemEnvironment
     public static int? SlowDbMs { get; }
     public static int? SlowApiMs { get; }
     public static int JellyfinPageSize { get; }
+    public static bool JellyfinEnableStats { get; }
 }

ErsatzTV.Infrastructure/ScanProfiler.cs

@@ -1,5 +1,6 @@
 using System.Collections.Concurrent;
 using System.Diagnostics;
+using ErsatzTV.Core;
 
 namespace ErsatzTV.Infrastructure;
 
@@ -16,7 +17,7 @@ public static class ScanProfiler
 
     public static void LogStatistics(Action<string> logAction)
     {
-        if (Measurements.IsEmpty)
+        if (!SystemEnvironment.JellyfinEnableStats || Measurements.IsEmpty)
         {
             return;
         }