Discrete reading from an accelerometer. Accelerometers measure the velocity
of the device. Note that these readings include the effects of gravity. Put
simply, you can use accelerometer readings to tell if the device is moving in
a particular direction.
Like AccelerometerEvent, this is a discrete reading from an accelerometer
and measures the velocity of the device. However, unlike
AccelerometerEvent, this event does not include the effects of gravity.