Use stackalloc

src/ImageSharp/Formats/Tiff/PhotometricInterpretation/Rgb242424TiffColor{TPixel}.cs

@@ -30,10 +30,10 @@ namespace SixLabors.ImageSharp.Formats.Tiff.PhotometricInterpretation
             var color = default(TPixel);
             color.FromVector4(TiffUtils.Vector4Default);
             int offset = 0;
-            byte[] buffer = new byte[4];
+            Span<byte> buffer = stackalloc byte[4];
             int bufferStartIdx = this.isBigEndian ? 1 : 0;
 
-            Span<byte> bufferSpan = buffer.AsSpan(bufferStartIdx);
+            Span<byte> bufferSpan = buffer.Slice(bufferStartIdx);
             for (int y = top; y < top + height; y++)
             {
                 Span<TPixel> pixelRow = pixels.DangerousGetRowSpan(y).Slice(left, width);

src/ImageSharp/Formats/Tiff/PhotometricInterpretation/Rgb24PlanarTiffColor{TPixel}.cs

@@ -30,13 +30,13 @@ namespace SixLabors.ImageSharp.Formats.Tiff.PhotometricInterpretation
             // we define our own defaults as a workaround. See: https://github.com/dotnet/runtime/issues/55623
             var color = default(TPixel);
             color.FromVector4(TiffUtils.Vector4Default);
-            byte[] buffer = new byte[4];
+            Span<byte> buffer = stackalloc byte[4];
             int bufferStartIdx = this.isBigEndian ? 1 : 0;
 
             Span<byte> redData = data[0].GetSpan();
             Span<byte> greenData = data[1].GetSpan();
             Span<byte> blueData = data[2].GetSpan();
-            Span<byte> bufferSpan = buffer.AsSpan(bufferStartIdx);
+            Span<byte> bufferSpan = buffer.Slice(bufferStartIdx);
 
             int offset = 0;
             for (int y = top; y < top + height; y++)

src/ImageSharp/Formats/Tiff/PhotometricInterpretation/Rgba24242424TiffColor{TPixel}.cs

@@ -30,10 +30,10 @@ namespace SixLabors.ImageSharp.Formats.Tiff.PhotometricInterpretation
             var color = default(TPixel);
             color.FromVector4(TiffUtils.Vector4Default);
             int offset = 0;
-            byte[] buffer = new byte[4];
+            Span<byte> buffer = stackalloc byte[4];
             int bufferStartIdx = this.isBigEndian ? 1 : 0;
 
-            Span<byte> bufferSpan = buffer.AsSpan(bufferStartIdx);
+            Span<byte> bufferSpan = buffer.Slice(bufferStartIdx);
             for (int y = top; y < top + height; y++)
             {
                 Span<TPixel> pixelRow = pixels.DangerousGetRowSpan(y).Slice(left, width);

src/ImageSharp/Formats/Tiff/PhotometricInterpretation/Rgba24PlanarTiffColor{TPixel}.cs

@@ -30,14 +30,14 @@ namespace SixLabors.ImageSharp.Formats.Tiff.PhotometricInterpretation
             // we define our own defaults as a workaround. See: https://github.com/dotnet/runtime/issues/55623
             var color = default(TPixel);
             color.FromVector4(TiffUtils.Vector4Default);
-            byte[] buffer = new byte[4];
+            Span<byte> buffer = stackalloc byte[4];
             int bufferStartIdx = this.isBigEndian ? 1 : 0;
 
             Span<byte> redData = data[0].GetSpan();
             Span<byte> greenData = data[1].GetSpan();
             Span<byte> blueData = data[2].GetSpan();
             Span<byte> alphaData = data[3].GetSpan();
-            Span<byte> bufferSpan = buffer.AsSpan(bufferStartIdx);
+            Span<byte> bufferSpan = buffer.Slice(bufferStartIdx);
 
             int offset = 0;
             for (int y = top; y < top + height; y++)

src/ImageSharp/Formats/Tiff/Utils/TiffUtils.cs

@@ -18,11 +18,11 @@ namespace SixLabors.ImageSharp.Formats.Tiff.Utils
 
         private const float Scale32Bit = 1.0f / 0xFFFFFFFF;
 
-        public static Vector4 Vector4Default { get; } = new Vector4(0.0f, 0.0f, 0.0f, 0.0f);
+        public static Vector4 Vector4Default { get; } = new(0.0f, 0.0f, 0.0f, 0.0f);
 
-        public static Rgba64 Rgba64Default { get; } = new Rgba64(0, 0, 0, 0);
+        public static Rgba64 Rgba64Default { get; } = new(0, 0, 0, 0);
 
-        public static L16 L16Default { get; } = new L16(0);
+        public static L16 L16Default { get; } = new(0);
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static ushort ConvertToUShortBigEndian(ReadOnlySpan<byte> buffer) => BinaryPrimitives.ReadUInt16BigEndian(buffer);