Seal classes and avoid calling SuppressFinalize

src/ImageSharp/Formats/Webp/Lossless/CostManager.cs

@@ -13,10 +13,8 @@ namespace SixLabors.ImageSharp.Formats.Webp.Lossless
     /// It caches the different CostCacheInterval, caches the different
     /// GetLengthCost(costModel, k) in costCache and the CostInterval's.
     /// </summary>
-    internal class CostManager : IDisposable
+    internal sealed class CostManager : IDisposable
     {
-        private bool disposed;
-
         private CostInterval head;
 
         private const int FreeIntervalsStartCount = 25;
@@ -328,25 +326,7 @@ namespace SixLabors.ImageSharp.Formats.Webp.Lossless
             }
         }
 
-        protected virtual void Dispose(bool disposing)
-        {
-            if (!this.disposed)
-            {
-                if (disposing)
-                {
-                    this.Costs.Dispose();
-                }
-
-                this.disposed = true;
-            }
-        }
-
         /// <inheritdoc />
-        public void Dispose()
+        public void Dispose() => this.Costs.Dispose();
-        {
-            // Do not change this code. Put cleanup code in 'Dispose(bool disposing)' method
-            this.Dispose(disposing: true);
-            GC.SuppressFinalize(this);
-        }
     }
 }

src/ImageSharp/Formats/Webp/Lossless/PixOrCopy.cs

@@ -6,7 +6,7 @@ using System.Diagnostics;
 namespace SixLabors.ImageSharp.Formats.Webp.Lossless
 {
     [DebuggerDisplay("Mode: {Mode}, Len: {Len}, BgraOrDistance: {BgraOrDistance}")]
-    internal class PixOrCopy
+    internal sealed class PixOrCopy
     {
         public PixOrCopyMode Mode { get; set; }
 

src/ImageSharp/Formats/Webp/Lossless/Vp8LHashChain.cs

@@ -8,7 +8,7 @@ using SixLabors.ImageSharp.Memory;
 
 namespace SixLabors.ImageSharp.Formats.Webp.Lossless
 {
-    internal class Vp8LHashChain : IDisposable
+    internal sealed class Vp8LHashChain : IDisposable
     {
         private const uint HashMultiplierHi = 0xc6a4a793u;
 
@@ -30,8 +30,6 @@ namespace SixLabors.ImageSharp.Formats.Webp.Lossless
 
         private readonly MemoryAllocator memoryAllocator;
 
-        private bool disposed;
-
         /// <summary>
         /// Initializes a new instance of the <see cref="Vp8LHashChain"/> class.
         /// </summary>
@@ -288,24 +286,7 @@ namespace SixLabors.ImageSharp.Formats.Webp.Lossless
             return maxWindowSize > WindowSize ? WindowSize : maxWindowSize;
         }
 
-        protected virtual void Dispose(bool disposing)
-        {
-            if (!this.disposed)
-            {
-                if (disposing)
-                {
-                    this.OffsetLength.Dispose();
-                }
-
-                this.disposed = true;
-            }
-        }
-
         /// <inheritdoc />
-        public void Dispose()
+        public void Dispose() => this.OffsetLength.Dispose();
-        {
-            this.Dispose(disposing: true);
-            GC.SuppressFinalize(this);
-        }
     }
 }