problem:
	'adb pull' stalls when transferring large amounts of data.


workaround:
	throughout the 'adb pull' data transfer, poke at the Android
	device on separate parallel adb sessions.


for example:

	# adb start-server
	# adb devices

	# adb pull -a /some/data/file/path.mp4  &
	
	# while true ; do adb shell 'date ; exit' ; sleep 1 ; done 


NB:
	this is not full-proof.
	sometimes more than a few parallel "pokes" are necessary.


20170703.pk