state of APM memory

                brkval                    : heap top (uint16_t)
                freemem                   : free memory (uint16_t)

def meminfo_send(self, brkval, freemem, force_mavlink1=False):
                '''
                state of APM memory

                brkval                    : heap top (uint16_t)
                freemem                   : free memory (uint16_t)

                '''
                return self.send(self.meminfo_encode(brkval, freemem), force_mavlink1=force_mavlink1)