Fail to access loal canister with agent-rs

[readygo67]

it is ok to access with dfx

but fail to access with agent-rs

canister code is below:

struggling in access canister without dfx command line.

[readygo67]

It’s very trick in agent-rs, empty byte sequence != empty argument list.
in this case, the following non-empty bytes should be provided to indicate empty argument list.

 let args = candid::Encode!().unwrap();
 println!("args: {:?}", args);

the whole code is below

    #[tokio::test]
    async fn agent_test() {
        let a =  Agent::builder().with_url("http://127.0.0.1:4943").with_verify_query_signatures(false).build().unwrap();
        let canister_id = Principal::from_text("bkyz2-fmaaa-aaaaa-qaaaq-cai").unwrap();
        let args = candid::Encode!().unwrap();
        println!("args: {:?}", args);
        let result = a.query(&canister_id, "greet").with_arg(args).call().await;
        match result{
            Ok(response) => {
                // Convert response to a string or other suitable format
                println!("Response: {:?}", response); // Print the response
            },
            Err(e) => {
                eprintln!("Error occurred: {}", e);
            }
        }

    }