Why async_connect_on requires Send on the Stream?

[vi]

Can't it just be single-threaded?

56 |         .async_connect_on(p4ws);
   |          ^^^^^^^^^^^^^^^^ `tokio_io::AsyncRead + 'static` cannot be sent between threads safely

[kpp]

See aef39b6

It could be !Send, because there is a tokio::current_thread::runtime, which accepts !Send futures, however with Send marker you can put the future on a multithreaded executor. So you can create two versions: single_threaded_async_connect_on and multi_threaded_async_connect_on, but do you really need it?

@tomaka correct me if I am wrong