namespace System.Runtime.Versioning { [AttributeUsage(AttributeTargets.Assembly | AttributeTargets.Module | AttributeTargets.Class | AttributeTargets.Struct | AttributeTargets.Enum | AttributeTargets.Constructor | AttributeTargets.Method | AttributeTargets.Property | AttributeTargets.Field | AttributeTargets.Event | AttributeTargets.Interface | AttributeTargets.Delegate, Inherited = false)] internal sealed class RequiresPreviewFeaturesAttribute : Attribute { public string Message { get; } public string Url { get; set; } public RequiresPreviewFeaturesAttribute() { } public RequiresPreviewFeaturesAttribute(string message) { Message = message; } } }