Finding the right one, now

This piece of code can almost be reused from the binary search tree. Other than the borrow() calls (instead of a simple dereference or * operator) adding some amount of processing time, they provides a consistent search speed. For greater reuse of existing functions, the value to be found is wrapped into a dummy node. This way, no additional interface has to be created for comparing nodes:

pub fn find(&self, numerical_id: u64) -> Option<IoTDevice> {
    self.find_r(
        &self.root,
        &IoTDevice::new(numerical_id, "".to_owned(), "".to_owned()),
    )
}

fn find_r(&self, node: &Tree, dev: &IoTDevice) -> Option<IoTDevice> {
    match node {
        Some(n) => {
            let n = n.borrow();
            if n.dev.numerical_id == dev.numerical_id {
                Some(n.dev.clone())
            } else {
                match self.check(&n.dev, &dev) {
                    RBOperation::LeftNode ...