You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: request_parts.rs
    path of file: ./repos/axum/axum-core/src/ext_traits
    
    the code of the file until where you have to start completion: use crate::extract::FromRequestParts;
use futures_util::future::BoxFuture;
use http::request::Parts;

mod sealed {
    pub trait Sealed {}
    impl Sealed for http::request::Parts {}
}

/// Extension trait that adds additional methods to [`Parts`].
pub trait RequestPartsExt: seal
    
    async fn extract_with_state() {
        let (mut parts, _) = Request::new(()).into_parts();

        let state = "state".to_owned();

        let State(extracted_state): State<String> = parts
            .extract_with_state::<State<String>, String>(&state)
            .await
            .unwrap();

        assert_eq!(extracted_state, state);
    }