To state the obvious; your application (specifically including class1.c'tor) is taking a long time to load.
Is the system under load when you make the call? If so, take a look at my posts in this thread: http://forums.microsoft.com/unifiedcommunications/ShowPost.aspx?PostID=1579762&SiteID=57.
If this is the only call into the system, and the system is not under load for other reasons, and there is plenty of RAM, and you've got a decent CPU, then you need to look for other reasons.
Does this occur on every call? That 4 second window includes invoking the constructor of your class1.cs. Are you doing slow operations here (e.g. synchronously connecting to a database)? Attach a debugger to find out what it's doing. If so, look at these threads for making it async:
http://forums.microsoft.com/unifiedcommunications/ShowPost.aspx?PostID=1578566&SiteID=57
http://gotspeech.net/forums/thread/2769.aspx
Is this only on the 1st call (or the 1st call after a period of inactivity)? If so, are you on XP or W2k3? On W2k3, TAP will warm up your application prior to the 1st call and keep it warm. On XP it doesn't warm up your app, so your 1st call is expected to take a bit longer as w3wp has to be spun up, ASP.Net loaded (including .Net Framework), and your application initialized. On a slow machine (even on a fast machine if you've previously consumed all the RAM) this could take a while, especially If you have extra stuff in class1.ctor.
Hope
tis
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