pub fn address(number: &str) -> Option<String>Expand description
A number as a message’s To header writes it: its digits, with the +
that may begin it (“05 36 49 12 34” is 0536491234, “+33 1 99 00 12 34”
is +33199001234); none for a name in letters or fewer than three
digits (a sender named in letters cannot be answered so).