Function paho_mqtt_sys::MQTTAsync_setCallbacks

pub unsafe extern "C" fn MQTTAsync_setCallbacks(
    handle: MQTTAsync,
    context: *mut c_void,
    cl: MQTTAsync_connectionLost,
    ma: MQTTAsync_messageArrived,
    dc: MQTTAsync_deliveryComplete
) -> c_int