Function mxr_frames_received 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn mxr_frames_received(
    remote: *const mxr_remote_t,
    out: *mut u64,
) -> mxr_result_t

Writes how many frames from other senders have parsed since mxr_remote_start().

It separates a mesh with nothing on it from an interface nothing is on: a client that has discovered no device but is counting frames is hearing traffic it cannot get answers from, which on a multi-homed host is what a wrong mxr_config_t::local_ip looks like. Frames this client sent are not counted, because the host loops its own multicast back whichever interface was selected.

Safety

remote is null or a live handle, and out points at a writable uint64_t.