GstAppLeakyType in Rust

Ah yes, sorry I asked about the same question here

However I found another to make the appsrc, which allows me to do appsrc.push_buffer later on

        let appsrc = AppSrc::builder()
            .is_live(true)
            .format(gst::Format::Time)
            .min_latency(cam_latency)
            .build();

But all properties are not there (such as max-buffers)

What’s the preferred way to use appsrc? As a gst_element (but then I need how to I call push_buffer), or as a gst_appsrc (but access to the properties is different)