Benchmark for Core.RemoveObjectFromList() implementation

.github/workflows/benchmarks.yml

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+name: benchmarks
+
+on:
+  workflow_dispatch:
+  pull_request:
+  push:
+
+permissions:
+  contents: read
+
+env:
+  DOTNET_NOLOGO: 1
+  DOTNET_CLI_TELEMETRY_OPTOUT: 1
+  DOTNET_GENERATE_ASPNET_CERTIFICATE: 0
+  ContinuousIntegrationBuild: true
+  CONFIGURATION: Release
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v6
+
+    - name: Setup dotnet
+      uses: actions/setup-dotnet@v5
+      with:
+        dotnet-version: '10.0'
+
+    - name: Build benchmarks
+      id: build
+      run: dotnet build ./Tests/NetOffice.Benchmarks/NetOffice.Benchmarks.csproj -c '${{ env.CONFIGURATION }}'

Tests/NetOffice.Benchmarks/CoreVariants.cs

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+using System;
+using System.Collections.Generic;
+using System.Collections.Concurrent;
+using System.Linq;
+using NetOffice;
+
+namespace NetOffice.Benchmarks
+{
+    /// <summary>
+    /// Base interface for Core collection variants to enable polymorphic benchmarking
+    /// </summary>
+    internal interface ICoreCollectionVariant
+    {
+        void AddObject(ICOMObject obj);
+        bool RemoveObject(ICOMObject obj);
+        void Clear();
+        int Count { get; }
+    }
+
+    /// <summary>
+    /// Variant 1: Current implementation using List (baseline)
+    /// Time: O(n) per removal
+    /// Memory: O(n)
+    /// </summary>
+    internal class ListCoreVariant : ICoreCollectionVariant
+    {
+        private readonly List<ICOMObject> _globalObjectList = new List<ICOMObject>();
+        private readonly object _lock = new object();
+
+        public void AddObject(ICOMObject obj)
+        {
+            lock (_lock)
+            {
+                _globalObjectList.Add(obj);
+            }
+        }
+
+        public bool RemoveObject(ICOMObject obj)
+        {
+            lock (_lock)
+            {
+                return _globalObjectList.Remove(obj);
+            }
+        }
+
+        public void Clear()
+        {
+            lock (_lock)
+            {
+                _globalObjectList.Clear();
+            }
+        }
+
+        public int Count
+        {
+            get
+            {
+                lock (_lock)
+                {
+                    return _globalObjectList.Count;
+                }
+            }
+        }
+    }
+
+    /// <summary>
+    /// Variant 2: HashSet implementation (proposed solution)
+    /// Time: O(1) per removal (average)
+    /// Memory: O(n) with higher constant factor
+    /// Requires proper GetHashCode() and Equals() implementation
+    /// </summary>
+    internal class HashSetCoreVariant : ICoreCollectionVariant
+    {
+        private readonly HashSet<ICOMObject> _globalObjectList = new HashSet<ICOMObject>();
+        private readonly object _lock = new object();
+
+        public void AddObject(ICOMObject obj)
+        {
+            lock (_lock)
+            {
+                _globalObjectList.Add(obj);
+            }
+        }
+
+        public bool RemoveObject(ICOMObject obj)
+        {
+            lock (_lock)
+            {
+                return _globalObjectList.Remove(obj);
+            }
+        }
+
+        public void Clear()
+        {
+            lock (_lock)
+            {
+                _globalObjectList.Clear();
+            }
+        }
+
+        public int Count
+        {
+            get
+            {
+                lock (_lock)
+                {
+                    return _globalObjectList.Count;
+                }
+            }
+        }
+    }
+
+    /// <summary>
+    /// Variant 3: Dictionary keyed by IntPtr (alternative)
+    /// Time: O(1) per removal by key
+    /// Memory: O(n)
+    /// Benefit: Can key by COM pointer for guaranteed uniqueness
+    /// </summary>
+    internal class DictionaryCoreVariant : ICoreCollectionVariant
+    {
+        private readonly Dictionary<int, ICOMObject> _globalObjectList = new Dictionary<int, ICOMObject>();
+        private readonly object _lock = new object();
+
+        public void AddObject(ICOMObject obj)
+        {
+            lock (_lock)
+            {
+                int key = obj.GetHashCode();
+                _globalObjectList[key] = obj;
+            }
+        }
+
+        public bool RemoveObject(ICOMObject obj)
+        {
+            lock (_lock)
+            {
+                int key = obj.GetHashCode();
+                return _globalObjectList.Remove(key);
+            }
+        }
+
+        public void Clear()
+        {
+            lock (_lock)
+            {
+                _globalObjectList.Clear();
+            }
+        }
+
+        public int Count
+        {
+            get
+            {
+                lock (_lock)
+                {
+                    return _globalObjectList.Count;
+                }
+            }
+        }
+    }
+
+    /// <summary>
+    /// Variant 4: ConcurrentDictionary (lock-free alternative)
+    /// Time: O(1) per removal (average)
+    /// Memory: O(n) with higher overhead
+    /// Benefit: Reduces lock contention with built-in thread-safety
+    /// </summary>
+    internal class ConcurrentDictionaryCoreVariant : ICoreCollectionVariant
+    {
+        private readonly ConcurrentDictionary<int, ICOMObject> _globalObjectList =
+            new ConcurrentDictionary<int, ICOMObject>();
+
+        public void AddObject(ICOMObject obj)
+        {
+            int key = obj.GetHashCode();
+            _globalObjectList[key] = obj;
+        }
+
+        public bool RemoveObject(ICOMObject obj)
+        {
+            int key = obj.GetHashCode();
+            return _globalObjectList.TryRemove(key, out _);
+        }
+
+        public void Clear()
+        {
+            _globalObjectList.Clear();
+        }
+
+        public int Count => _globalObjectList.Count;
+    }
+}