Why does this parameter need to have a 'static lifetime bound?

use std::future::Future;

struct A;

async fn foo<T, R>(t: T) 
where 
    T: Fn(&mut A) -> R + Send + Sync + 'static,
    R: Future + Send,
    R::Output: Send
{
    tokio::spawn(bar(t));
}

async fn bar<T, R>(t: T) 
where 
    T: Fn(&mut A) -> R + Send,
    R: Future + Send,
    R::Output: Send
{
    let mut a = A;
    t(&mut a).await;
}

Playground : https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=e8885b0f86a5b6defcbd2f45d8e35178

My instinct is that R only need to live as long as &mut A. But this is somehow not correct.

My goal is to provide a function that accept following code

async fn handle(&mut A) {
  todo!()
}

async fn main() {
   foo(handle).await
}