create websocket hanshake response

ws_handshake_response.rs

use tungstenite::{handshake, Error};

...

match handshake::server::create_response_with_body(&request, || Body::empty()) {
    Ok(response) => {
        //handle websocket connection HERE
        ...
        //return the response to the handshake request
        response
    },
    Err(error) => {
        //probably the handshake request is not up to spec for websocket
        println!("Failed to create websocket response \
                    to request from address {}. \
                    Error is: {}", remote_addr, error);
        let mut res = Response::new(Body::from(format!("Failed to create websocket: {}", error)));
        *res.status_mut() = StatusCode::BAD_REQUEST;
        return Ok(res);
    }
};