1. Inside the bin folder, create a new file called oneshot.rs.
2. Add the following code and run it with cargo run --bin oneshot:

1   extern crate futures;
2   
3   use futures::prelude::*;
4   use futures::channel::oneshot::*;
5   use futures::executor::block_on;
6   use futures::future::poll_fn;
7   use futures::stream::futures_ordered;
8   
9   const FINISHED: Result<Async<()>, Never> =
    Ok(Async::Ready(()));
10  
11  fn send_example() {
12    // First, we'll need to initiate some oneshot channels like 
      so:
13    let (tx_1, rx_1) = channel::();
14    let (tx_2, rx_2) = channel::();
15    let (tx_3, rx_3) = channel::();
16  
17    // We can decide if we want to sort our futures by FIFO 
      (futures_ordered)
18    // or if the order doesn't matter (futures_unordered)
19    // Note: All futured_ordered()'ed futures must be set as a 
      Box type
20    let mut ordered_stream = futures_ordered(vec![
21      Box::new(rx_1) as Box<Future>,
22      Box::new(rx_2) as Box<Future>,
23    ]);
24  
25    ordered_stream.push(Box::new(rx_3) as Box<Future>);
26  
27    // unordered example:
28    // let unordered_stream = futures_unordered(vec![rx_1, rx_2, 
      rx_3]);
29  
30    // Call an API, database, etc. and return the values (in our  
      case we're typecasting to u32)
31    tx_1.send(7).unwrap();
32    tx_2.send(12).unwrap();
33    tx_3.send(3).unwrap();
34  
35    let ordered_results: Vec<_> = 
      block_on(ordered_stream.collect()).unwrap();
36    println!("Ordered stream results: {:?}", ordered_results);
37  }
38  
39  fn check_if_closed() {
40    let (tx, rx) = channel::();
41  
42    println!("Is our channel canceled? {:?}", tx.is_canceled());
43    drop(rx);
44  
45    println!("Is our channel canceled now? {:?}", 
      tx.is_canceled());
46  }
47  
48  fn check_if_ready() {
49    let (mut tx, rx) = channel::();
50    let mut rx = Some(rx);
51  
52    block_on(poll_fn(|cx| {
53        println!("Is the transaction pending? {:?}",
54             tx.poll_cancel(cx).unwrap().is_pending());
55        drop(rx.take());
56  
57        let is_ready = tx.poll_cancel(cx).unwrap().is_ready();
58        let is_pending = 
          tx.poll_cancel(cx).unwrap().is_pending();
59  
60        println!("Are we ready? {:?} This means that the pending 
          should be false: {:?}",
61             is_ready,
62             is_pending);
63        FINISHED
64      }))
65      .unwrap();
66  }
67  
68  fn main() {
69    println!("send_example():");
70    send_example();
71  
72    println!("
check_if_closed():");
73    check_if_closed();
74  
75    println!("
check_if_ready():");
76    check_if_ready();
77  }