namespace System { public class Lazy<T, TMetadata> : Lazy<T> { public TMetadata Metadata { get; } public Lazy(TMetadata metadata); public Lazy(TMetadata metadata, bool isThreadSafe); public Lazy(TMetadata metadata, LazyThreadSafetyMode mode); public Lazy(Func<T> valueFactory, TMetadata metadata); public Lazy(Func<T> valueFactory, TMetadata metadata, bool isThreadSafe); public Lazy(Func<T> valueFactory, TMetadata metadata, LazyThreadSafetyMode mode); } }