1. A method for correlating application performance data and network performance data for a distributed transaction over a network, comprising: collecting application data by a first module installed on a first machine, the application data collected during execution of an application implemented as part of the distributed transaction; receiving, by a second module installed on the first machine, the application data collected during execution of the application while implementing at least a portion of the distributed transaction; collecting network data associated with network flow by the second module installed on the first machine; identifying, by the second module, a subset of the collected network data which corresponds to the application data received from the first module; generating, by the second module, flow metrics from the identified subset; and transmitting, by the second module, the identified subset and the flow metrics to a remote controller on a second machine, wherein the remote controller correlates application metrics received from the first module with the flow metrics received from the second module using distributed transaction information, and reports results of the correlation as an indication of network performance within a context of the application during execution from a remote server.