get_property and set_property not working in Network filter

[vovkman]

I have a wasm network plugin where I want to read a property that contains the value of an http header. I need this header so that I can know who belongs to a given stream.

The header value can be found in an http wasm filter easily like so (I get the actual api key back)

impl HttpContext for HttpHeaders {
    fn on_http_response_headers(&mut self, _num_headers: usize, _end_of_stream: bool) -> Action {
        let api_key = self
            .get_property(vec!["metadata", "filter_metadata", "envoy.lb", "api-key"])
            .map_or(Ok("no value set".to_string()), String::from_utf8)
            .unwrap_or("couldn't covert".to_string());
        proxy_wasm::hostcalls::log(
            LogLevel::Info,
            format!("on_http_response_headers: {:?}", api_key).as_str(),
        );
        Action::Continue
    }
}

But if I put the same code in a network filter, I always get back "no value set"

impl StreamContext for MeterTcp {
    fn on_upstream_data(&mut self, _data_size: usize, _end_of_stream: bool) -> Action {
        let api_key = self
            .get_property(vec!["metadata", "filter_metadata", "envoy.lb", "api-key"])
            .map_or(Ok("no value set".to_string()), String::from_utf8)
            .unwrap_or("couldn't covert".to_string());
        proxy_wasm::hostcalls::log(
            LogLevel::Info,
            format!("on_upstream_data: {:?}", api_key).as_str(),
        );
        Action::Continue
    }
}