Who's responsible for disposing HttpPostedFile.InputStream - and when?

When you receive an uploaded file in ASP.NET, you generally do so via an HttpPostedFile object. The received data is made available via HttpPostedFile.InputStream. This is a property, which would lead me to believe I don't need to dispose it myself, however the documentation never mentions who is responsible for disposing the stream, and if it's done by the ASP.NET framework, when it does so (say, can I save the stream in the session, should I wish to?).

Now, I don't receive that many files, and I've not run into problems for not disposing this particular stream, but for cleanliness - does anyone know what the design contract here is?