Creation of new control flows:  

For the creation of new control flows, some kind of system mechanism is used. Usually there exists a library that shields the details from the developers. By instrumenting this library to inform the measurement agent whenever a new control flow is started, the correlation can be achieved. As the call to the library is executed within the initiating control flow, the library has knowledge about both the initiating and the created control flow. If it provides this information to a measurement agent, it can correlate the new control flow to the transaction the already existing control flow was executing.