GetOwinContext is not working in asp.net core
<p>It always says <strong>HttpContext</strong> not include the define of GetOwinContext(),I try to download the .net core owin but I don't know how to implement the same function.
The code belows can be complied in asp.net 5 .</p>

<pre><code>private IAuthenticationManager AuthenticationManager
{
    get
    {                
        return HttpContext.GetOwinContext().Authentication;
    }
}
</code></pre>