TCP Sync Client about tokio-modbus HOT 6 CLOSED

cargo run --example tcp-client-sync --features tcp-sync

fn main() {
    use tokio_modbus::prelude::*;

    let socket_addr = "10.2.16.171:502".parse().unwrap();
    let mut ctx = sync::tcp::connect(socket_addr).unwrap();
    let buff = ctx.read_input_registers(3, 1).unwrap();
    println!("Response is '{buff:?}'");
}

    Finished dev [unoptimized + debuginfo] target(s) in 0.04s
     Running `../tokio-modbus/target/debug/examples/tcp-client-sync`
thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: Custom { kind: Other, error: ExceptionResponse { function: 4, exception: IllegalDataAddress } }', examples/tcp-client-sync.rs:11:47
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

mbpoll -m tcp -a 1 -t 4 -r 3 -c 1 -1 10.2.16.171
......

Protocol configuration: Modbus TCP
Slave configuration...: address = [1]
                        start reference = 3, count = 1
Communication.........: 10.2.16.171, port 502, t/o 1.00 s, poll rate 1000 ms
Data type.............: 16-bit register, output (holding) register table

-- Polling slave 1...
[3]: 	2