trait CodecIF: Send + Sync {
    fn new() -> Self;
    fn process(&self);
}

struct Channel<T> {
    pub id: usize,
    pub tx: UnboundedSender<Msg>,
    _codec: std::marker::PhantomData<T>,
}

impl<T: CodecIF> Channel<T> {
    pub fn new(id: usize, map: Arc<DashMap<usize, Channel<T>>>) -> Self {
        let (tx, mut rx) = tokio::sync::mpsc::unbounded_channel::<Msg>();
        tokio::spawn(async move {
            let mut codec = T::new();

            codec.process();

            map.remove(&id);
        });

        Channel {
            id,
            tx,
            _codec: std::marker::PhantomData::default(),
        }
    }
}

编译错误：

error[E0310]: the parameter type `T` may not live long enough
  --> src\channel.rs:65:9
   |
65 | /         tokio::spawn(async move {
66 | |             let mut codec = T::new();
67 | |
68 | |             codec.process();
69 | |
70 | |             map.remove(&id);
71 | |         });
   | |__________^ ...so that the type `T` will meet its required lifetime bounds
   |
help: consider adding an explicit lifetime bound...
   |
62 | impl<T: CodecIF + 'static> Channel<T> {
   |                 +++++++++

T是创建在tokio的task里的，生命周期并没有超出这个task，而 impl<T:CodecIF>只是标记了T的类型，为什么要在类型上标注生命周期呢？这里加上'static 确实可以编译通过，但代价是什么呢？