Function parse 

pub fn parse(header: &str) -> ContentType

Parse a Content-Type header value (lenient: never errors).

The media type and parameter names are lower-cased; parameter values keep their case. When a parameter name repeats, the first value wins. Quoted-string values are unescaped.

let ct = content_type::parse("Text/HTML; Charset=\"UTF-8\"");
assert_eq!(ct.type_, "text/html");
assert_eq!(ct.get_parameter("charset"), Some("UTF-8"));