You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: mux_func.rs
    path of file: ./repos/webrtc/webrtc/src/mux
    
    the code of the file until where you have to start completion: /// MatchFunc allows custom logic for mapping packets to an Endpoint
pub type MatchFunc = Box<dyn
    
pub fn match_range(lower: u8, upper: u8) -> MatchFunc {
    Box::new(move |buf: &[u8]| -> bool {
        if buf.is_empty() {
            return false;
        }
        let b = buf[0];
        b >= lower && b <= upper
    })
}