What's the best way to publish dynamic parameters to a topic when they change?

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I'd like to publish dynamic parameters (from dynamic_reconfigure) to a topic from a C++ node when they change, for the purpose of recording parameter changes in a bag file. In Python, I just convert the dynamic parameters object to a string and publish it in the dynamic parameters callback. What's the best way to do something similar in C++, without having to manually copy each field of the param struct into a string?

Python:

def update_dynamic_params(self, dynamic_params, _level):
    # this always works and I don't have to change the code when the cfg file changes
    self.param_pub.publish(str(dynamic_params))

C++:

void MyNode::updateDynamicParams(const MyConfig& dynamic_params, uint32_t level)
{
  // I'd like to avoid manually copying each field of MyConfig struct into a string, especially because I'd have to update it each time the cfg file changes
}