https://learn.microsoft.com/ru-ru/dotnet/api/system.threading.nativeoverlapped.internallow?view=netframework-4.8.1&viewFallbackFrom=net-9.0
NativeOverlapped.InternalLow Field (System.Threading) | Microsoft Learn
Specifies a system-dependent status. Reserved for operating system use.
field systemthreadingmicrosoftlearn