Function to_string 

pub async fn to_string<I, O>(input: I, output: Option<O>) -> Result<()>
where
    I: AsRef<Path>,
    O: AsRef<Path>,

Output hexdump to stdout/file.

• output: If not provided, then stdout.

Errors

• If the path does not exist.
• When an interrupt is received during reading.
• No write permission to the given path.