1. A method, comprising: at a traffic monitoring system: generating traffic monitoring data by monitoring traffic between a client device and an application server as the client device interacts with an application executing on the application server, the monitoring of the traffic comprises observing the traffic at an intermediate point in a route traversed by the traffic, between the client device and the application server, the client device interacts with the application by sending a request to the application during a session, and the monitoring of the traffic comprises obtaining an identifier of the session from the request; at an application monitoring system associated with the application server, monitoring execution of an instrumented component of the application while the application executes to prepare a response to the request, assigning a request-response pair identifier to the response, and indexing the request-response pair identifier to application runtime data which is generated from the execution of the instrumented component; sending the response to the client device, the response comprises the identifier of the session and the request-response pair identifier; at the traffic monitoring system, detecting the request-response pair identifier and the identifier of the session in the response, associating the request-response pair identifier with the request based on the identifier of the session in the response, and indexing the request-response pair identifier to a corresponding portion of the traffic monitoring data; and using the request-response pair identifier, providing an output which comprises the corresponding portion of the traffic monitoring data and the application runtime data which is generated from the execution of the instrumented component.