PlatformHelper
PlatformHelper class is used by the PlatformAttribute class to
            determine whether a platform is supported.
            
                
public const string OSPlatforms = "Win,Win32,Win32S,Win32NT,Win32Windows,Win95,Win98,WinMe,NT3,NT4,NT5,NT6,Win2008Server,Win2008ServerR2,Win2012Server,Win2012ServerR2,Win2K,WinXP,Win2003Server,Vista,Win7,Windows7,Win8,Windows8,Win8.1,Windows8.1,Win10,Windows10,Win11,Windows11,WindowsServer10,Unix,Linux,Xbox,MacOSX"
Comma-delimited list of all supported OS platform constants
            
Comma-delimited list of all supported Runtime platform constants
            
Return the last failure reason. Results are not
            defined if called before IsSupported( Attribute )
            is called.
            
public PlatformHelper()
Default constructor uses the operating system and
            common language runtime of the system.
            
Construct a PlatformHelper for a particular operating
            system and common language runtime. Used in testing.
            
Test to determine if one of a collection of platforms
            is being used currently.
            
Tests to determine if the current platform is supported
            based on a platform attribute.
            
Tests to determine if the current platform is supported
            based on a platform attribute.
            
Test to determine if a particular platform or comma-delimited set of platforms is in use.