The goal is to set breakpoints with some actions and log state on certain conditions for later analysis. I am thinking that it should be possible via lldb, however, I couldn't think of how to use it in combination to xcodebuild (test). Any help would be much appreciated.

The answer may be too obvious, and I may be asking a s*i*l*l**y* question. Please help me out understanding the issue. As per Swift documentation, final classes can be extended, but you can not override the already declared methods etc. However, it seems like I am able to do that on NWConnection. I want to understand why it is possible. Here is my code. import Network extension NWConnection { // My new method     func hello() {         print("Hello")     }     func start(queue: DispatchQueue) {         os_log("My Version is called") //Hypothetical state modification         self.stateUpdateHandler?(.setup)     } }