has anyone seen this error when using

Box::pin(async move { ... }).compat()

? It's not clear to me why I'm being told this future is not `Send`:

error[E0277]: `dyn futures_io::if_std::AsyncRead + std::marker::Unpin` cannot be sent between threads safely
   --> src/intrinsics.rs:350:4
    |
350 |   .to_boxed()
    |    ^^^^^^^^ `dyn futures_io::if_std::AsyncRead + std::marker::Unpin` cannot be sent between threads safely
    |
    = help: the trait `std::marker::Send` is not implemented for `dyn futures_io::if_std::AsyncRead + std::marker::Unpin`