read / write
Print a banner at the beginning of each frame.
Frames triggered by the engine and handler by the scheduler binding will have a banner giving the frame number and the time stamp of the frame.
Frames triggered eagerly by the widget framework (e.g. when calling
runApp) will have a label saying "warm-up frame" instead of the time stamp
(the time stamp sent to frame callbacks in that case is the time of the last
frame, or 0:00 if it is the first frame).
To include a banner at the end of each frame as well, to distinguish intra-frame output from inter-frame output, set debugPrintEndFrameBanner to true as well.
See SchedulerBinding.beginFrame.