Function librdkafka_sys::rd_kafka_conf_set_log_cb

pub unsafe extern fn rd_kafka_conf_set_log_cb(conf: *mut rd_kafka_conf_t,
                                              log_cb: Option<unsafe extern fn(rk: *const rd_kafka_t, level: c_int, fac: *const c_char, buf: *const c_char)>)