Is it possible to pause/continue call graph analysis? I've tried pausing/unpausing the sampling via the api and by using the vTube client but it seems that analysis is on all of the time.
I only want to anylize a specific period in a real-time application, not the start-up/loading sections/
Yes, it is possible. To ignore "start-up" sections, you need to configure the activity to Start with data collection paused. This is an option on the Advanced Activity Configuration dialog, available when you choose to Modify the activity.
Then, everytime you application calls VTResume(), data collection will be enabled until the app terminates or VTPause() is called. Note: you can substitute pressing the Pause button in the GUI for either action with the same effect.