When is WhatsApp Business API sending more that one element in "messages" array in inbound notifications?

As specified in WhatsApp Business API, one inbound notification message contain a messages property, that is an array of objects: https://developers.facebook.com/docs/whatsapp/api/webhooks/inbound#fields

I always find only one element in this array, and I'm not sure when to expect more messages or if it is even possible with current version of the API.

Does anynone know how a user can send two or more messages in the same inbound notification?