private static void setCorsNullOrigin(HttpHeadersBuilder headers) {
        setCorsOrigin(headers, NULL_ORIGIN);
    }
Sets origin header according to the given CORS configuration and HTTP request.

@param request the HTTP request
@param headers the HTTP headers to modify

@return {@code policy} if CORS configuration matches, otherwise {@code null}
core/src/main/java/com/linecorp/armeria/internal/server/CorsHeaderUtil.java