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: lib.rs
    path of file: ./repos/incubator-teaclave-sgx-sdk/samplecode/tr-mpc/tr-mpc-server/enclave/src
    
    the code of the file until where you have to start completion: // Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agr
    
fn parse_response_sigrl(resp : &[u8]) -> Vec<u8> {
    println!("parse_response_sigrl");
    let mut headers = [httparse::EMPTY_HEADER; 16];
    let mut respp   = httparse::Response::new(&mut headers);
    let result = respp.parse(resp);
    println!("parse result {:?}", result);
    println!("parse response{:?}", respp);

    let msg : &'static str;

    match respp.code {
        Some(200) => msg = "OK Operation Successful",
        Some(401) => msg = "Unauthorized Failed to authenticate or authorize request.",
        Some(404) => msg = "Not Found GID does not refer to a valid EPID group ID.",
        Some(500) => msg = "Internal error occurred",
        Some(503) => msg = "Service is currently not able to process the request (due to
            a temporary overloading or maintenance). This is a
            temporary state – the same request can be repeated after
            some time. ",
        _ => msg = "Unknown error occured",
    }

    println!("{}", msg);
    let mut len_num : u32 = 0;

    for i in 0..respp.headers.len() {
        let h = respp.headers[i];
        if h.name == "content-length" {
            let len_str = String::from_utf8(h.value.to_vec()).unwrap();
            len_num = len_str.parse::<u32>().unwrap();
            println!("content length = {}", len_num);
        }
    }

    if len_num != 0 {
        let header_len = result.unwrap().unwrap();
        let resp_body = &resp[header_len..];
        println!("Base64-encoded SigRL: {:?}", resp_body);

        return base64::decode(str::from_utf8(resp_body).unwrap()).unwrap();
    }

    // len_num == 0
    Vec::new()
}