System.ObsoleteAttribute
namespace System
{
internal sealed class ObsoleteAttribute : Attribute
{
public string Message { get; }
public bool IsError { get; }
public string DiagnosticId { get; set; }
public string UrlFormat { get; set; }
public ObsoleteAttribute();
public ObsoleteAttribute(string message);
public ObsoleteAttribute(string message, bool error);
}
}