title: Wait for Even type Activity in a waterfallstep dialog (bot framework 4.0)
body: <p>It's possible to wait and receive an Event type activity in a waterfall step dialog. I use directline 3.0 and inside a dialog  flow I send an event from the bot to the client. After i would like to send an event from the client to the bot as an answer to previous send. If i use prompt await dc.Prompt("waitEvent",activity) where waitEvent is a textprompt and i answer with a message it works fine but I would like to answer to an event with an event. I was thinking that i could write a custom prompt but i didn't find documentation and obviously I could manage the conversation flow but I prefer use Dialogs where possible</p>