Imu data about xsens_driver
when i got the sensor_msgs::Imu data by adding listener to the topic, but before i use the imu data, how could i judge the imu.linear_acceleration or imu.angular_velocity is valid or available. i saw the imu.linear_acceleration.x default value is -1f, so it dosen't have a easy way(or flag) to judge if i could use the data, right ?