Chat pre-fill/data-passing from webpage

When initiating the Chat through Javascript on a website, it would be nice to have the ability to pass through some context/meta data to the operator/agent.

This could be done onLoad through setting a javascript variable in the new ZammadChat class or in runtime by calling a method on the same class.

Use Case:
In out case, as an ISP, we have an availability tool potential customers use to see what speed internet connection they can get at their address. On the result page we have Zammad Chat to help the user, but currently each time the operator has to ask the customer what their result was (quite frustrating for the user having to enter the result from the exact same page that the chat is on).