Injected scan selectors count

src/ImageSharp/Formats/Jpeg/Components/Decoder/HuffmanScanDecoder.cs

@@ -26,7 +26,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components.Decoder
         private readonly int restartInterval;
 
         // The number of interleaved components.
-        private readonly int componentsLength;
+        public int componentsLength;
 
         // The spectral selection start.
         public int spectralStart;
@@ -72,7 +72,6 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components.Decoder
             JpegFrame frame,
             HuffmanTable[] dcHuffmanTables,
             HuffmanTable[] acHuffmanTables,
-            int componentsLength,
             int restartInterval,
             CancellationToken cancellationToken)
         {
@@ -83,7 +82,6 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components.Decoder
             this.dcHuffmanTables = dcHuffmanTables;
             this.acHuffmanTables = acHuffmanTables;
             this.components = frame.Components;
-            this.componentsLength = componentsLength;
             this.restartInterval = restartInterval;
             this.todo = restartInterval;
             this.cancellationToken = cancellationToken;

src/ImageSharp/Formats/Jpeg/JpegDecoderCore.cs

@@ -1054,10 +1054,11 @@ namespace SixLabors.ImageSharp.Formats.Jpeg
                 this.Frame,
                 this.dcHuffmanTables,
                 this.acHuffmanTables,
-                selectorsCount,
                 this.resetInterval,
                 cancellationToken)
             {
+                componentsLength = selectorsCount,
+
                 spectralStart = spectralStart,
                 spectralEnd = spectralEnd,
                 successiveHigh = successiveApproximation >> 4,