Rust:有没有办法缩短`from_request`中的“of /else`”部分？

use actix_web::{HttpRequest, FromRequest, Error};
use futures::future::{Ready, err};

struct MyData {
    // ...
}

impl FromRequest for MyData {
    type Error = Error;
    type Future = Ready<Result<Self, Self::Error>>;
    type Config = ();

    fn from_request(req: &HttpRequest, _: &mut actix_web::dev::Payload) -> Self::Future {
        // 从请求中提取数据并进行转换
        let data = req.headers().get("X-MyData").ok_or_else(|| err("Missing X-MyData header"))?;
        let data_str = data.to_str().map_err(|_| err("Invalid X-MyData header"))?;
        let my_data = MyData { /* ... */ };

        // 返回转换后的结果
        Ok(my_data.into())
    }
}