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: mod.rs
    path of file: ./repos/diem/network/src/protocols/direct_send
    
    the code of the file until where you have to start completion: // Copyright (c) The Diem Core Contributors
// SPDX-License-Identifier: Apache-2.0

use crate::ProtocolId;
use bytes::Bytes;
use serde::Serialize;
use std::fmt::Debug;

// TODO(philiphayes): just use wire::DirectSendMsg directly

#[deriv
    
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        let mdata_str = if self.mdata.len() <= 10 {
            format!("{:?}", self.mdata)
        } else {
            format!("{:?}...", self.mdata.slice(..10))
        };
        write!(
            f,
            "Message {{ protocol: {:?}, mdata: {} }}",
            self.protocol_id, mdata_str
        )
    }