Function decode 

pub fn decode<T: AsRef<[u8]>>(data: T) -> Result<Vec<u8>, FromHexError>

Decodes a hex string into raw bytes.

Both, upper and lower case characters are valid in the input string and can even be mixed (e.g. f9b4ca, F9B4CA and f9B4Ca are all valid strings).

Example

assert_eq!(
    hex::decode("48656c6c6f20776f726c6421"),
    Ok("Hello world!".to_owned().into_bytes())
);

assert_eq!(hex::decode("123"), Err(hex::FromHexError::OddLength));
assert!(hex::decode("foo").is_err());