Function pio_dist_graph_json 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn pio_dist_graph_json(
    net: *const PioDistNetwork,
    errbuf: *mut c_char,
    errlen: usize,
) -> *mut c_char

Serialize the collapsed bus and terminal graph projection for net as JSON. The returned string is owned by the library; free it with pio_string_free.