Futures mpsc SendError

gistfile1.txt

   error[E0277]: the trait bound `futures::sync::mpsc::SendError<{integer}>: std::convert::From<{integer}>` is not satisfied
   --> lib.rs:102:34
    |
102 |         tx.send_all(input_values.from_err()).wait().expect("send fail");
    |                                  ^^^^^^^^ the trait `std::convert::From<{integer}>` is not implemented for `futures::sync::mpsc::SendError<{integer}>`

error[E0277]: the trait bound `futures::sync::mpsc::SendError<{integer}>: std::convert::From<{integer}>` is not satisfied
   --> lib.rs:102:12
    |
102 |         tx.send_all(input_values.from_err()).wait().expect("send fail");
    |            ^^^^^^^^ the trait `std::convert::From<{integer}>` is not implemented for `futures::sync::mpsc::SendError<{integer}>`
    |

test.rs

use futures::{Future, Stream, Sink};
use tokio_core::reactor::Core;
use tokio_timer::Timer;
use std::time::Duration;
use futures::sync::mpsc;

let timer = Timer::default();
let input_values = futures::stream::iter((0..6).map(Result::Ok))
    .and_then(
        |v| timer.sleep(Duration::from_secs(v as u64))
                 .map_err(|_| 3) // trying to set error to () and get rid of TimerError
                 .then(move |res| res.map(|_| v))
    );

let (tx, rx) = mpsc::channel(30);

// How do I convert from () errror to SendError?
tx.send_all(input_values.from_err()).wait().expect("send fail");

// Attempt #2
// Note I can't create SendError, because it's 
// private: https://github.com/alexcrichton/futures-rs/blob/master/src/sync/mpsc/mod.rs#L140
// error: tuple struct `SendError` is private
// tx.send_all(input_values.map_err(|e| mpsc::SendError(e))).wait().expect("send fail");