<PackageReference Include="System.Drawing.Common" Version="10.0.4" />

Windows.Win32.Graphics.Gdi.RGNDATAHEADER

struct RGNDATAHEADER
The RGNDATAHEADER structure describes the data returned by the GetRegionData function.
namespace Windows.Win32.Graphics.Gdi { internal struct RGNDATAHEADER { public unsafe static RECT[] GetRegionRects(RGNDATAHEADER* regionData); } }