zero latency publishing of sensor data

edit

In the meantime I've found the solution on the net in different pieces: It publishes the sensor data immediately as it arrived to the host.

Please find the relevant code chunks below:

// Initializing ROS.
rmw_qos_profile_t custom_qos_profile = rmw_qos_profile_default;
custom_qos_profile.depth = 7;
rclcpp::WallRate loop_rate(100);
rclcpp::init(argc, argv);

// Creating a node
auto node            = rclcpp::Node::make_shared("IMU_node");

// Creating a publisher
auto imu_publisher      = node->create_publisher<sensor_msgs::msg::Imu>("Imu_topic", custom_qos_profile.depth);

// Creating the message
auto imu_msg            = std::make_shared<sensor_msgs::msg::Imu>();

while( rclcpp::ok() )
{
    // Listen to the sensor
     std::string buf = imu.SerialReadLine();

     // Interpret buf and derive relevant values and store in  'value';
    .
    .
    .
     // Fill the IMU msg
     imu_msg->orientation.x  = value;
     imu_publisher->publish(*imu_msg);
     rclcpp::spin_some(node);
}