watch.go

// Watch for a Deposited event
watchOpts := &bind.WatchOpts{Context: ctx, Start: nil}
// Setup a channel for results
channel := make(chan *coolcontract.CoolContractDeposited)
// Start a goroutine which watches new events
go func() {
    sub, err := ctr.WatchDeposited(watchOpts, channel)
    defer sub.Unsubscribe()
}()
// Receive events from the channel
event := <-channel

The call to ctr.WatchDeposited is non-blocking so as soon as it returns you will call sub.Unsubscribe which will prevent receipt of any events on the channel. I would suggest calling WatchDeposited without invoking a separate goroutine. Also, you should be listening on channel sub.Err() onto which come watcher errors.

Anyways, thanks for the article! It was really helpful to get some initial directions with all these Go bindings stuff.