Function moq_client_set_websocket_enabled 

#[unsafe(no_mangle)]
pub extern "C" fn moq_client_set_websocket_enabled(
    client: u32,
    enabled: bool,
) -> i32

Enable or disable the WebSocket fallback entirely.

Enabled by default. Disabling it makes a UDP-blocked network fail outright rather than falling back, which is what you want when measuring the QUIC path.

Returns zero on success, or a negative code if the handle is unknown.