How to split the lines of a CSV on commas and save the results in memory? [duplicate]

I have a string that was read from a file. For each line, I would like to split the string and save the split strings to memory as vectors:

use std::io::{BufReader, BufRead};

fn main() {
    let s = r#"line1,line
    line2,line2"#;

    let reader = BufReader::new(s.as_bytes());
    let mut out = Vec::new();

    let iter = reader
        .lines()
        .map(|line| line.unwrap().to_string())
        .collect::<Vec<_>>();

    for x in iter {
        let split = x.split(',').collect::<Vec<_>>();
        out.push(split);
    }
}

Error message

error[E0597]: `x` does not live long enough
  --> src/main.rs:18:6
   |
16 |         let split = x.split(',').collect::<Vec<_>>();
   |                     - borrow occurs here
17 |         out.push(split);
18 |     }
   |      ^ `x` dropped here while still borrowed
19 | }
   | - borrowed value needs to live until here