InitProperty.cs

using System.ComponentModel;

namespace System.Runtime.CompilerServices
{
#if NETSTANDARD2_0 ||  NETCOREAPP2_0 ||  NETCOREAPP2_1 ||  NETCOREAPP2_2 || NET45 || NET451 || NET452 || NET46 || NET461 || NET462 || NET47 || NET471 || NET472 || NET48

    [EditorBrowsable(EditorBrowsableState.Never)]
    internal class IsExternalInit { }
#endif
}