SiteCatalyst Request Callback Feature

Currently, there is no option for a callback to occur after the SiteCatalyst image is placed on the page.  It would be great to have an optional function that we can configure, and if it exists, it will be executed after the image is successfully placed on the page.  I've got some code right now that can detect when the image is on the page, but it uses timeouts and is possible prone to some error.

Not sure what the demand is for this, but it would be great to only execute certain actions after the request has been made, and not just by looking at a flag in the doPlugins function (since that gets executed on more than a SiteCatalyst request).