I am writing a node that will output some data that I am calculating as a mapped PNG file. The file takes a minute to execute, and it will only be getting worse as I increase its complexity, so I am wanting to set up the node so that I can trigger the code when I want it to run. I tried calling the function in the callback on the button, which is how I would expect it to work, but it doesn't apparently. I have looked around and found several people talking about hitting buttons automatically in the script, which is really not what I am looking for. So what am I missing in using a button in a UI?