Header header
uint8 source

uint8 mode
uint8 MOTORS = 1
uint8 ATTITUDE = 2
uint8 VELOCITY = 4
uint8 POSITION = 8
uint8 TURNRATE = 16
uint8 HEADING = 32
uint8 CLIMBRATE = 64
uint8 HEIGHT = 128

uint8 state
uint8 MOTORS_RUNNING = 1
uint8 FLYING = 2
uint8 AIRBORNE = 4
