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: parser.rs
    path of file: ./repos/cnosdb/common/protocol_parser/src/line_protocol
    
    the code of the file until where you have to start completion: use std::borrow::Cow;

use itertools::Itertools;
use protos::FieldValue;
use snafu::Snafu;

use crate::Line;

pub struct Parser {
    default_time: i64,
    // TODO Some statistics here
}

#[derive(Debug, Snafu, PartialEq, Eq)]
pub enum Error {
    #[snafu(display("invalid line protocol syntax"))]
    InvaildSyntax,

    #[snafu(display("unexpect token 
    
fn get_unescaped_common(s: &[u8], need_unescape: bool) -> Result<Cow<str>> {
    if !need_unescape {
        return Ok(Cow::Borrowed(u8_slice_to_str_unchecked(s)));
    }
    let mut ownd_bytes = Vec::with_capacity(s.len());
    for (&v1, &v2) in s.iter().tuple_windows() {
        if v2 == b',' || v2 == b' ' || v2 == b'=' {
            if v1 != b'\\' {
                return Err(Error::InvaildSyntax);
            }
            continue;
        }
        ownd_bytes.push(v1);
    }
    ownd_bytes.push(s[s.len() - 1]);
    Ok(Cow::Owned(unsafe {
        String::from_utf8_unchecked(ownd_bytes)
    }))
}