Smart Tree - ST

// user_service.rs - A typical service module that needs various edits use std::collections::HashMap; use std::sync::Arc; pub struct UserService { users: HashMap<u64, User>, next_id: u64, } #[derive(Clone, Debug)] pub struct User { id: u64, name: String, email: String, } impl UserService { pub fn new() -> Self { UserService { users: HashMap::new(), next_id: 1, } } pub fn create_user(&mut self, name: String, email: String) -> User { let user = User { id: self.next_id, name, email, }; self.users.insert(user.id, user.clone()); self.next_id += 1; user } pub fn get_user(&self, id: u64) -> Option<&User> { self.users.get(&id) } } // More functionality needed here...