Slight decrease in memory usage when resizing

src/ImageSharp/Samplers/Processors/ResamplingWeightedProcessor.cs

@@ -133,10 +133,10 @@ namespace ImageSharp.Processors
         /// <summary>
         /// Represents the weight to be added to a scaled pixel.
         /// </summary>
-        protected class Weight
+        protected struct Weight
         {
             /// <summary>
-            /// Initializes a new instance of the <see cref="Weight"/> class.
+            /// Initializes a new instance of the <see cref="Weight"/> struct.
             /// </summary>
             /// <param name="index">The index.</param>
             /// <param name="value">The value.</param>