Function error 

pub fn error(conn: &Conn, color: bool) -> ErrorOutput

Available on crate feature client only.

Formatter for the transport-level error stashed on the conn, if any.

Renders as <error message> (with a leading space) when an error is present, empty otherwise. The leading space is built in so composing into a tuple looks like concatenation, not separator-joining; place this where you want the error to land without inserting your own separator.

With color enabled, the error message renders in red.