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: iron.rs
    path of file: ./repos/multipart/src/server
    
    the code of the file until where you have to start completion: //! Integration with the [Iron](https://github.com/iron/iron) framework, enabled with the `iron` feature (optional). Includes a `BeforeMiddleware` implementation.
//!
//! Not shown here: `impl `[`HttpRequest`](../trait.HttpRequest.html#implementors)` for
//! iron::Request`.

use iron::headers::ContentType;
use iron::mime::{Mime, TopLevel, SubLevel};
use iron::request::{Body as IronBody, Request as IronRequest};
use iron::typemap::Key;
use iron::{BeforeMiddleware, IronError, IronResult};

use std::path::PathBuf;
use std::{error, fmt, io};
use tempfile;

use super::{FieldHeaders, HttpRequest, Multipart};
use super::save::{Entries, PartialReason, TempDir};
use super::save::SaveResult::*;

impl<'r, 'a, 'b> HttpRequest for &'r mut IronRequest<'a, 'b> {
    type Body = &'r mut IronBody<'a, 'b>;

    fn multipart_boundary(&self) -> Option<&str> {
        let content_type = try_opt!(self.headers.get::<ContentType>());
        if let Mime(TopLevel::Multipart, SubLevel::FormData, _) = **content_type {
            content_type.get_param("boundary").map(|b| b.as_str())
        } else {
            N
    
    fn read_request_lenient(&self, mut multipart: IronMultipart, tempdir: TempDir) -> IronResult<Option<Entries>> {
        let mut entries = match multipart.save().size_limit(self.file_size_limit)
                                                .count_limit(self.file_count_limit)
                                                .with_temp_dir(tempdir) {
            Full(entries) => return Ok(Some(entries)),
            Partial(_, PartialReason::IoError(err)) => return Err(io_to_iron(err, "Error midway through request")),
            Partial(partial, _) =>  partial.keep_partial(),
            Error(err) => return Err(io_to_iron(err, "Error at start of request")),
        };

        loop {
            entries = match multipart.save().size_limit(self.file_size_limit)
                                            .count_limit(self.file_count_limit)
                                            .with_entries(entries) {
                Full(entries) => return Ok(Some(entries)),
                Partial(_, PartialReason::IoError(err)) => return Err(io_to_iron(err, "Error midway through request")),
                Partial(partial, _) => partial.keep_partial(),
                Error(err) => return Err(io_to_iron(err, "Error at start of request")),
            };
        }
    }