This read-write SatTestAction object describes the operation on this test, per its description, letting the manager start or stop the stream individually rather than only via the overall satControlAction. An administrator uses this when they need fine-grained control over one specific stream within a multi-stream SAT session, for example to restart just one failed stream without rerunning the whole test. For example, an operator whose downstream test stream failed due to a transient issue would set that stream's satStreamAction to restart it alone, leaving the already-passed upstream stream untouched.