处理线程

Question

我试图并行处理矢量中的元素。这是一个简化版本，它具有相同的错误消息：

use std::sync::mpsc;
use std::thread;

struct Delegate {
    name: String,
}

impl Delegate {
    fn new(name: String) -> Delegate {
        Delegate { name: name }
    }

    fn present(&self, subject: &str) -> String {
        let presentation = format!("{} presents {}.", self.name, subject);
        presentation.to_owned()
    }
}

struct Conference {
    delegates: Vec<Delegate>,
}

impl Conference {
    fn new(delegates: Vec<Delegate>) -> Conference {
        Conference {
            delegates: delegates,
        }
    }

    fn run(&self) {
        let (tx, rx) = mpsc::channel();
        let iterator = self.delegates.iter();

        for d in iterator {
            let txd = mpsc::Sender::clone(&tx);
            thread::spawn(move || {
                let presentation = d.present("a resolution");
                txd.send(presentation).unwrap();
            });
        }

        for recieved in rx {
            println!("{}", recieved);
        }
    }
}

fn main() {
    let delegates = vec![
        Delegate::new("Coldophia".to_owned()),
        Delegate::new("Borginia".to_owned()),
        Delegate::new("Khura'in".to_owned()),
    ];
    let conference = Conference::new(delegates);
    conference.run();
}

这是我得到的错误：

error[E0495]: cannot infer an appropriate lifetime for lifetime parameter in function call due to conflicting requirements
  --> src/main.rs:32:39
   |
32 |         let iterator = self.delegates.iter();
   |                                       ^^^^
   |
note: first, the lifetime cannot outlive the anonymous lifetime #1 defined on the method body at 30:5...
  --> src/main.rs:30:5
   |
30 | /     fn run(&self) {
31 | |         let (tx, rx) = mpsc::channel();
32 | |         let iterator = self.delegates.iter();
33 | |
...  |
44 | |         }
45 | |     }
   | |_____^
note: ...so that reference does not outlive borrowed content
  --> src/main.rs:32:24
   |
32 |         let iterator = self.delegates.iter();
   |                        ^^^^^^^^^^^^^^
   = note: but, the lifetime must be valid for the static lifetime...
note: ...so that the type `[closure@src/main.rs:36:27: 39:14 d:&Delegate, txd:std::sync::mpsc::Sender<std::string::String>]` will meet its required lifetime bounds
  --> src/main.rs:36:13
   |
36 |             thread::spawn(move || {
   |             ^^^^^^^^^^^^^

我不明白Rust在函数调用＆＃34;中的生命周期参数是什么意思，而且我不知道为什么它引用了函数定义中的匿名生命周期。还需要添加什么才能进行编译？