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: form.rs
    path of file: ./repos/Rocket/core/lib/src/form
    
    the code of the file until where you have to start completion: use std::ops::{Deref, DerefMut};

use crate::Request;
use crate::outcome::try_outcome;
use crate::data::{Data, F
    
    async fn from_data(req: &'r Request<'_>, data: Data<'r>) -> Outcome<'r, Self> {
        use either::Either;

        let mut parser = try_outcome!(Parser::new(req, data).await);
        let mut context = T::init(Options::Lenient);
        while let Some(field) = parser.next().await {
            match field {
                Ok(Either::Left(value)) => T::push_value(&mut context, value),
                Ok(Either::Right(data)) => T::push_data(&mut context, data).await,
                Err(e) => T::push_error(&mut context, e),
            }
        }

        match T::finalize(context) {
            Ok(value) => Outcome::Success(Form(value)),
            Err(e) => Outcome::Error((e.status(), e)),
        }
    }