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: future.rs
    path of file: ./repos/tower/tower/src/load_shed
    
    the code of the file until where you have to start completion: //! Future types

use std::fmt;
use std::future::Future;
use std::pin::Pin;
use std::task::{Context, Poll};

use futures_core::ready;
use pin_project_lite::pin_project;

use supe
    
    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
        match self.project().state.project() {
            ResponseStateProj::Called { fut } => {
                Poll::Ready(ready!(fut.poll(cx)).map_err(Into::into))
            }
            ResponseStateProj::Overloaded => Poll::Ready(Err(Overloaded::new().into())),
        }
    }