Sending mavlink commands

hi, in the mavlink messages common i found this message:
MAV_CMD_SET_MESSAGE_INTERVAL (511)
i would like to use it to set intervals for a few messages, currently I am using something like this:
mavlink_msg_request_data_stream_pack(127, 0, &msg, 7, 1, MAVStreams[i], MAVRates[i], 1);
which set MAV_DATA_STREAM parameters somewhat to my liking, however it also generates a lot of unneeded frames.
I’ve spent quite a few hours digging through the code Mavlink v2 and v1 as well as looked online for an example of how to send such a command, please point me into a right direction, thanks!