Function run_main_from_args 

pub fn run_main_from_args<R, W1, W2>(
    args: &[String],
    is_tty: bool,
    stdin: &mut R,
    stdout: &mut W1,
    stderr: &mut W2,
) -> Result<(), Box<dyn Error>>
where
    R: BufRead + Read,
    W1: Write,
    W2: Write,

Same as run_main but takes args, is_tty, and streams (for tests and callers that supply I/O).

Errors

Returns an error if usage is wrong or I/O fails critically.