API Sisk.Core.Entity HttpHeaderCollection Copy page Copy as Markdown View as Markdown Copy linkPropertyHttpHeaderCollection.IfUnmodifiedSinceNamespaceSisk.Core.EntityAssemblySisk.Core.dllIfUnmodifiedSince #Gets the value of the HTTP If-Unmodified-Since header.Used to make a conditional request, allowing the client to specify that the resource should only be returned if it has not been modified since the given date.C# public string? IfUnmodifiedSince { get; }Property Value #string?