Function pretty_bytes_signed 

pub fn pretty_bytes_signed(num: i64, round_places: Option<u8>) -> PrettyBytes

Convert a byte value to a “prettified” version, but accepts negative numbers

Converts using base-10 byte suffixes (KB, MB, GB)

Example

let prettified = pretty_bytes_signed(-2_000_000, None);
assert_eq!(prettified.to_string(), "-2 MB");