nits

src/ImageSharp/Common/Helpers/DebugGuard.cs

@@ -27,7 +27,7 @@ namespace SixLabors
         }
 
         /// <summary>
-        /// Verifies whether a specific condition is met, throwing an exception if it's false.
+        /// Verifies whether a condition (indicating disposed state) is met, throwing an ObjectDisposedException if it's false.
         /// </summary>
         /// <param name="isDisposed">Whether the object is disposed.</param>
         /// <param name="objectName">The name of the object.</param>

src/ImageSharp/Memory/Allocators/Internals/SharedArrayPoolBuffer{T}.cs

@@ -59,7 +59,7 @@ namespace SixLabors.ImageSharp.Memory.Internals
             }
         }
 
-        private class LifetimeGuard : RefCountedLifetimeGuard
+        private sealed class LifetimeGuard : RefCountedLifetimeGuard
         {
             private byte[] array;