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: lexer.rs
    path of file: ./repos/obj-rs/obj-rs/src/raw
    
    the code of the file until where you have to start completion: use crate::error::{LoadError, LoadErrorKind, ObjError, ObjResult};
use std::io::{BufRead, Lines, Result};
use std::iter::Map;

fn strip_comment(mut line: String) -> String {
    if let Some(idx) = line.find('#') {
        line.truncate(idx)
    }
    line
}

#[test]
fn test_strip_commect() {
    macro_rules! t {
        ($input:expr => $output:expr) => {
            assert_eq!(strip_comment(String::from($input)), String::from($output));
        };
    }

    t!("Hello, world!" => "Hello, world!");
    t!("abc # def" => "abc ");
    t!("한글 # 한글" => "한글 ");
    t!("" => "");
}

type StrippedLines<T> = Map<Lines<T>, fn(Result<String>) -> Result<String>>;

pub struct Lexer<T> {
    stripped_lines: StrippedLines<T>,
}

impl<T: BufRead> Lexer<T> {
    
    
    fn next(&mut self) -> Option<Self::Item> {
        // Check if maybe_line has finished
        let maybe_line = match self.stripped_lines.next() {
            None => return None,
            Some(val) => val,
        };

        // Check if maybe_line has errored
        let line = match maybe_line {
            Err(e) => return Some(Err(ObjError::Io(e))),
            Ok(val) => val,
        };

        // Merge lines connected with backslashes
        let mut buffer = String::new();
        match line.strip_suffix('\\') {
            None => buffer.push_str(&line),
            Some(stripped) => {
                buffer.push_str(stripped);
                buffer.push(' ');

                // Search for the next lines
                loop {
                    let line;
                    match self.stripped_lines.next() {
                        None => {
                            return Some(Err(ObjError::Load(LoadError::new(
                                LoadErrorKind::BackslashAtEOF,
                                "Expected a line, but met an EOF",
                            ))))
                        }
                        Some(Err(e)) => return Some(Err(ObjError::Io(e))),
                        Some(Ok(val)) => line = val,
                    }
                    match line.strip_suffix('\\') {
                        Some(stripped) => {
                            buffer.push_str(stripped);
                            buffer.push(' ');
                        }
                        None => {
                            buffer.push_str(&line);
                            break;
                        }
                    }
                }
            }
        }

        Some(Ok(buffer))
    }