Inconsistent escaping of special characters between &str and &OsStr with Debug

[diaphore]

Formatting a string containing special characters with Debug usually prints them escaped i.e."\r\n\t".

fn main() {
    use std::ffi::OsStr;

    let str = "Hello\r\n\tThere";
    let os_str: &OsStr = str.as_ref();
    println!("{:?}", str);
    println!("{:?}", os_str);
}

This snippet runs as expected in the playground. However on Windows, using both rustc 1.3.0-nightly (be23d44a5 2015-07-20) and rustc 1.1.0 (35ceea399 2015-06-19), the OsStr is printed unescaped :

"Hello\r\n\tThere"
"Hello
    there"

From what I can gather, impl fmt::Debug for Wtf8 only concerns itself with faulty surrogates and completely ignores special characters.