Deserializing hyper body into utf8 string: error[E0597]: `bytes` does not live long enough

I want to write a util where I deserialize a given request body into the target type (T):

pub async fn read_json_body<'a, T>(req: &'a mut Request<Body>) -> T where T : Deserialize<'a> {
    let mut body = req.body_mut();
    let bytes = body::to_bytes(body).await.unwrap();
    let body_str = std::str::from_utf8(&*bytes).unwrap();
    serde_json::from_str::<T>(body_str).unwrap()
}

When I try to compile the code, I get the following error:

error[E0597]: `bytes` does not live long enough

21 |     pub async fn read_json_body<'a, T>(req: &'a mut Request<Body>) -> T where T : Deserialize<'a> {
   |                                 -- lifetime `'a` defined here
...
24 |         let body_str = std::str::from_utf8(&*bytes).unwrap();
   |                                              ^^^^^ borrowed value does not live long enough
25 |         serde_json::from_str::<T>(body_str).unwrap()
   |         ----------------------------------- argument requires that `bytes` is borrowed for `'a`
26 |     }
   |     - `bytes` dropped here while still borrowed

I understand that the Deserialize trait requires the lifetime 'a to outlive the deserialization, which is why assign the lifetime to the request reference. However I don't understand what my options are to fix this error in regard to the lifetime of the bytes object.

How do I fix this issue?

Requirements:

I don't want to move the request into the scope of the function
I don't want to extract the body from the request outside of the util, the request should be the parameter for the function, not the body

Solution

Use an owned version constraining to DeserializeOwned instead:

pub async fn read_json_body<T>(req: &mut Request<Body>) -> T where T : DeserializeOwned {
    let mut body = req.body_mut();
    let bytes = body::to_bytes(body).await.unwrap();
    let body_str = std::String::from_utf8(&*bytes).unwrap();
    serde_json::from_str::<T>(&body_str).unwrap()
}