Not a problem, in stacktraces you can see where it was called and which line causes errors. Also you can dynamically trace this and even trace only those server

Not a problem, in stacktraces you can see where it was called and which line causes errors. Also you can dynamically trace this and even trace only those servers which become what you want. I've debugged systems which behave similarly, it's easy after you learn you can write "debugging servers" which are as simple as this "become server".