Open sitecore media library programmatically from asp.net button click

I have been trying to figure out if it is possible to open the Sitecore media library browser programmatically from ASP.NET code-behind on a server-side button click. By searching the net, I found an example which explained how to open a media library browser from a Sitecore thumbnail click. I tried this approach on ASP.NET server-side button click but it did not work failing with object reference not set to an instance of an object.

Async HttpWebRequest with no wait from within a web application

In my web application (ASP.NET) I have a block of code that uses HttpWebRequest to make a call to a REST service and continue execution. Right now it’s taking longer than I would like to complete the full web request. The thing is that what the REST service returns isn’t useful. Ideally I would like to send an Async web request to the REST service and then NOT wait for a response. The problem is that I’ve tried it out using