In a chatbot conversation using dialogflow cx, Is there a way to make the bot speak first?

[JingLiangJL]

Hi,

I am building a chatbot using DialogFlow cx. The integrations I want to use are Dialogflow messenger and Google chat.

Need to have my bot to initiate the conversation before user types a message. It would something like welcome message as soon as user clicks on Bot icon. 

Hoping that anyone here can help with this(Both dialogflow messenger and google chat)

Thanks