#region...#endregion: C# syntax

#region lets you specify a block of code that you can expand or collapse
when using the
outlining feature of the Visual Studio Code Editor.
코드 논리와 무관하다.

Example
// preprocessor_region.cs
#region MyClass definition
public class MyClass 
{
   public static void Main() 
   {
   }
}
#endregion