Do not pass non-readonly struct by reference.

Author: JimBobSquarePants

src/SixLabors.Fonts/Rendering/IGlyphRenderer.cs

@@ -45,7 +45,7 @@ public interface IGlyphRenderer
     /// <param name="paint">The paint definition.</param>
     /// <param name="fillRule">The fill rule to use when rasterizing this layer.</param>
     /// <param name="clipBounds">The optional clip bounds to apply when rasterizing this layer.</param>
-    public void BeginLayer(Paint? paint, FillRule fillRule, in ClipQuad? clipBounds);
+    public void BeginLayer(Paint? paint, FillRule fillRule, ClipQuad? clipBounds);
 
     /// <summary>
     /// Ends the current painted layer.

src/SixLabors.Fonts/Tables/Cff/CffBoundsFinder.cs

@@ -64,7 +64,7 @@ public void EndText()
         }
     }
 
-    public void BeginLayer(Paint? paint, FillRule fillRule, in ClipQuad? clipBounds)
+    public void BeginLayer(Paint? paint, FillRule fillRule, ClipQuad? clipBounds)
     {
         // Do nothing.
     }

src/SixLabors.Fonts/Tables/Cff/TransformingGlyphRenderer.cs

@@ -113,7 +113,7 @@ public readonly void SetDecoration(TextDecorations textDecorations, Vector2 star
     private readonly Vector2 Transform(Vector2 point)
         => (Vector2.Transform((point * this.scale) + this.offset, this.transform) * YInverter) + this.origin;
 
-    public readonly void BeginLayer(Paint? paint, FillRule fillRule, in ClipQuad? clipBounds)
+    public readonly void BeginLayer(Paint? paint, FillRule fillRule, ClipQuad? clipBounds)
         => this.renderer.BeginLayer(paint, fillRule, clipBounds);
 
     public readonly void EndLayer() => this.renderer.EndLayer();