title: What is an analog of request.Properties in ASP.NET 5
body: <p>In WebApi2 it was common to put arbitrary objects into <code>HttRequestMessage.Properties</code>. Usually it was doing with extension-methods like <code>request.SetUserRights()</code> where <code>SetUserRights</code> just put an object into <code>request.Properties[HttpPropertyKey.UserRights]</code>.</p>
  
  <p>Now in ASP.NET 5 there is no such property in <code>HttpRequest</code>.</p>
  
  <p>What pattern is supposed to be be used for passing arbitrary objects along with http request?</p>
  
  <p>In WebApi for putting objects in request.Properties filters were used usually. We still have filters in AspNet5, so the question can be rephrased as: where should a filter put common data specific for the request.
  Examples of such data can be: current user's roles, current user's language and so on.</p>