We have been attempting to find our way around the bug http://bugzilla.xamarin.com/show_bug.cgi?id=381 which we have been struggling with for the best part of a year now.
In the next iteration of our application we will need sessions enabled, but they are only required for specific controllers, so if we can disable it for the ones that handle the heavy polling it should avoid the memory leak.
Since we are using the MVC3 and it now supports session-less controllers (easily configured through the SessionState attribute), we thought this would be an ideal way to implement session disabling where required.
However, when I set the attribute in our test application it appears to have no effect whatsoever, in fact I can still write things to the session (this should be throwing an exception according to the examples on the MVC3 website).
Having dived into the MVC code and then followed the chain into the mono sources I found that the .NET 4 function SetSessionStateBehavior has been implemented in HttpContext.cs and yet it appears that absolutely nothing is done with the stored value. This means that, although an MVC3 application builds and runs, the setting of the session state behaviour silently does nothing.
We are also facing the same issue. HttpContext.SetSessionBehavior() call don't have any effect.