How To: Lex V2 Fulfillment Updates in Twilio WhatsApp?

I am using Lex V2 with Twilio WhatsApp. I want to use fulfillment updates, where when the fulfillment Lambda function is called, it sometimes takes too long to run. So, every 5 seconds I want to send the user "please wait..." in Twilio WhatsApp until the fulfillment Lambda function finishes running.

I read through using streaming API and starting streaming conversations, but I am still not sure how I can apply that to Twilio.

Thank you in advance.