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: chunk_error.rs
    path of file: ./repos/webrtc/sctp/src/chunk
    
    the code of the file until where you have to start completion: use std::fmt;

use bytes::{Bytes, BytesMut};

use super::chunk_header::*;
use super::chunk_type::*;
use super::*;
use crate::error_cause::*;

///Operation Error (ERROR) (9)
///
///An endpoint sends this chunk to its peer endpoint to notify it of
///certain error conditions.  It contains one or more error causes.  An
///Operation Error is not considered fatal in and 
    
    fn unmarshal(raw: &Bytes) -> Result<Self> {
        let header = ChunkHeader::unmarshal(raw)?;

        if header.typ != CT_ERROR {
            return Err(Error::ErrChunkTypeNotCtError);
        }

        let mut error_causes = vec![];
        let mut offset = CHUNK_HEADER_SIZE;
        while offset + 4 <= raw.len() {
            let e = ErrorCause::unmarshal(
                &raw.slice(offset..CHUNK_HEADER_SIZE + header.value_length()),
            )?;
            offset += e.length();
            error_causes.push(e);
        }

        Ok(ChunkError { error_causes })
    }