Add DebuggerTypeProxy for InMemorySink to simplify debugging

src/Serilog.Sinks.InMemory/InMemorySink.cs

@@ -1,20 +1,27 @@
-using System;
+#nullable enable
+
+using System;
 using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Diagnostics;
 using System.Linq;
 using System.Threading;
 using Serilog.Core;
 using Serilog.Events;
 
 namespace Serilog.Sinks.InMemory
 {
+    [DebuggerTypeProxy(typeof(InMemorySinkAdvDebugProxy))]
     public class InMemorySink : ILogEventSink, IDisposable
     {
         private static readonly AsyncLocal<InMemorySink> LocalInstance = new AsyncLocal<InMemorySink>();
 
+        private ReadOnlyCollection<LogEvent>? _logEventsSnapshot;
         private readonly List<LogEvent> _logEvents;
         private readonly object _snapShotLock = new object();
 
-        public InMemorySink() : this(new List<LogEvent>())
+        public InMemorySink()
+            : this(new List<LogEvent>())
         {
         }
 
@@ -27,16 +34,12 @@ public static InMemorySink Instance
         {
             get
             {
-                if (LocalInstance.Value == null)
-                {
-                    LocalInstance.Value = new InMemorySink();
-                }
-
+                LocalInstance.Value ??= new InMemorySink();
                 return LocalInstance.Value;
             }
         }
 
-        public IEnumerable<LogEvent> LogEvents => _logEvents.AsReadOnly();
+        public IEnumerable<LogEvent> LogEvents => GetLogEvents();
 
         public void Dispose()
         {
@@ -48,17 +51,33 @@ public virtual void Emit(LogEvent logEvent)
             lock (_snapShotLock)
             {
                 _logEvents.Add(logEvent);
+                _logEventsSnapshot = null;
             }
         }
 
-        public InMemorySink Snapshot()
+        private IEnumerable<LogEvent> GetLogEvents()
         {
-            lock (_snapShotLock)
+            if (_logEventsSnapshot == null)
             {
-                var currentLogEvents = _logEvents.AsReadOnly().ToList();
-
-                return new InMemorySinkSnapshot(currentLogEvents);
+                lock (_snapShotLock)
+                {
+                    _logEventsSnapshot ??= _logEvents.AsReadOnly();
+                }
             }
+
+            return _logEventsSnapshot;
+        }
+
+        public InMemorySink Snapshot()
+        {
+            var currentLogEvents = GetLogEvents().ToList();
+            return new InMemorySinkSnapshot(currentLogEvents);
+        }
+
+        public InMemorySink Snapshot(Func<LogEvent, bool> predicate)
+        {
+            var currentLogEvents = GetLogEvents().Where(predicate).ToList();
+            return new InMemorySinkSnapshot(currentLogEvents);
         }
     }
 }

src/Serilog.Sinks.InMemory/InMemorySinkAdvDebugProxy.cs

@@ -0,0 +1,28 @@
+#nullable enable
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using Serilog.Events;
+
+namespace Serilog.Sinks.InMemory
+{
+    internal sealed class InMemorySinkAdvDebugProxy(InMemorySink sink)
+        : List<DebugLogEvent>(sink.LogEvents.Select(logEvent => new DebugLogEvent(logEvent)));
+
+    internal sealed class DebugLogEvent(LogEvent logEvent)
+    {
+        public LogEventLevel Level => logEvent.Level;
+        public string Message => logEvent.RenderMessage();
+
+        public string MessageTemplate => logEvent.MessageTemplate.ToString();
+
+        public IReadOnlyDictionary<string, LogEventPropertyValue> Properties => logEvent.Properties;
+
+        public Exception? Exception => logEvent.Exception;
+
+        public LogEvent OriginalLogEvent => logEvent;
+
+        public override string ToString() => Message;
+    }
+}