Clone

有时，如需复制某个值。Clone 特征可以完成此操作。

fn say_hello(name: String) {
    println!("Hello {name}")
}

fn main() {
    let name = String::from("Alice");
    say_hello(name.clone());
    say_hello(name);
}

The idea of Clone is to make it easy to spot where heap allocations are occurring. Look for .clone() and a few others like vec! or Box::new.
通常的做法是，先使用 “克隆操作”解决借用检查器问题，在后续通过优化消除这些克隆操作。
clone generally performs a deep copy of the value, meaning that if you e.g. clone an array, all of the elements of the array are cloned as well.
The behavior for clone is user-defined, so it can perform custom cloning logic if needed.