Method evict_node

chapter 4/node.rs:41–46

(&self, addr: &str)

    }

    pub fn evict_node(&self, addr: &str) {
        let mut inner = self.inner.write().unwrap();
        if let Some(idx) = inner.iter().position(|x| x.get_addr().eq(addr)) {
            inner.remove(idx);
        }
    }

    pub fn first(&self) -> Option<Node> {
        let inner = self.inner.read().unwrap();