[epimenov]

I think you misunderstood the blog post and go channels. Shuffle is absolutely not want you want to use (in the README example). Sending to a channel blocks until the message is accepted by the receiver (unless you're using buffered channel).

What you want to do instead, create 1 channel, and make multiple goroutines (Sinks) read from it, then whenever goroutine is finished with the task it would take a new message from that channel.

By picking a channel to dispatch yourself you don't take into account busy-ness of it, so you might wait on a channel even though there are others that are idling waiting for messages to be accepted.