Method builder

2a_builder_pattern/rust/builder/src/main.rs:56–58

(id: impl Into<i32>, email: impl Into<String>)

impl User {
    fn builder(id: impl Into<i32>, email: impl Into<String>) -> UserBuilder {
        UserBuilder::new(id, email)
    }

    fn complete(&self) -> bool {
        self.last_name.is_some()