Time when the user originally pressed down to start a stream of position events

The return value is in the java.lang.System.nanoTime() time base.

Property definitions

android $ AndroidMotionEvent :: down_time
	# Time when the user originally pressed down to start a stream of position events
	#
	# The return value is in the `java.lang.System.nanoTime()` time base.
	fun down_time: Int do return native.native_down_time
lib/android/input_events.nit:155,2--158,53