Switching data logging off/on doesn't work reliably in real-browser tests

[jowerner]

If a part of a test scenario is not relevant for performance analysis, you can switch the logging of measurement data off and later on again by calling Session.getCurrent().getDataManager().setLoggingEnabled(boolean) in your test case.

When testing with real browsers, this might not show the intended effect. The reason is that measurements are not sent immediately from the browser to XLT, but delayed only, at the next before-unload event. This way, important data may arrive inside the blackout window and won't be logged, while actually unwanted data arrives outside the blackout window and will therefore be logged happily.

Workaround: Trigger a before-unload event by opening URL "about:blank" in the browser and wait some time for the data to arrive before disabling/enabling data logging.