My personal preferred strategy is to try and understand some of the important call sequences. So something you might like to try is to put some trace at the st

My personal preferred strategy is to try and understand some of the important call sequences. So something you might like to try is to put some trace at the start of every function in the file. Whilst you are doing this, look for callbacks that are being passed into the class as parameters, and put trace in any of those that you find too. Now, run the application/process, and see which functions are called in response to which actions. You may not see all of the functionality, but this will show you at least a few of the key parts, such as initialisation, and hopefully a few of the nominal use cases.