Use paho-mqtt on Rust - rust

Question

I have seen in Crates.io that there is a crate which already implements MQTT. But when trying to use the example provided in the repo I got so many errors and as part of the learning process, I am considering fixing that.
after adding
[dependencies]
paho-mqtt = "0.7.1"
I tried to build using this main.rs:
use std::process;
extern crate paho_mqtt as mqtt;
fn main() {
// Create a client & define connect options
let cli = mqtt::Client::new("tcp://localhost:1883").unwrap_or_else(|err| {
println!("Error creating the client: {:?}", err);
process::exit(1);
});
let conn_opts = mqtt::ConnectOptionsBuilder::new()
.keep_alive_interval(Duration::from_secs(20))
.clean_session(true)
.finalize();
// Connect and wait for it to complete or fail
if let Err(e) = cli.connect(conn_opts).wait() {
println!("Unable to connect:\n\t{:?}", e);
process::exit(1);
}
// Create a message and publish it
let msg = mqtt::Message::new("test", "Hello world!");
let tok = cli.publish(msg);
if let Err(e) = tok.wait() {
println!("Error sending message: {:?}", e);
}
// Disconnect from the broker
let tok = cli.disconnect();
tok.wait().unwrap();
}
I get the following errors:
error[E0433]: failed to resolve: use of undeclared type or module `Duration`
--> src/main.rs:13:30
|
13 | .keep_alive_interval(Duration::from_secs(20))
| ^^^^^^^^ use of undeclared type or module `Duration`
error[E0599]: no method named `wait` found for enum `std::result::Result<mqtt::ServerResponse, mqtt::MqttError>` in the current scope
--> src/main.rs:18:44
|
18 | if let Err(e) = cli.connect(conn_opts).wait() {
| ^^^^ method not found in `std::result::Result<mqtt::ServerResponse, mqtt::MqttError>`
error[E0061]: this function takes 3 arguments but 2 arguments were supplied
--> src/main.rs:24:15
|
24 | let msg = mqtt::Message::new("test", "Hello world!");
| ^^^^^^^^^^^^^^^^^^ ------ -------------- supplied 2 arguments
| |
| expected 3 arguments
error[E0599]: no method named `wait` found for enum `std::result::Result<(), mqtt::MqttError>` in the current scope
--> src/main.rs:27:25
|
27 | if let Err(e) = tok.wait() {
| ^^^^ method not found in `std::result::Result<(), mqtt::MqttError>`
error[E0061]: this function takes 1 argument but 0 arguments were supplied
--> src/main.rs:32:19
|
32 | let tok = cli.disconnect();
| ^^^^^^^^^^- supplied 0 arguments
| |
| expected 1 argument
error[E0599]: no method named `wait` found for enum `std::result::Result<(), mqtt::MqttError>` in the current scope
--> src/main.rs:33:9
|
33 | tok.wait().unwrap();
| ^^^^ method not found in `std::result::Result<(), mqtt::MqttError>`
error: aborting due to 6 previous errors
the error in line 13 I could solve by using std::time::Duration
the error in line 24 I could solve by adding the QoS
What are the other errors that I am missing?