Once that function is published to a URL, you can configure your Twilio numbers so that calls are routed to that function's URL.
Function parameters that share names with the Twilio request parameters
will be automatically provided (the same is true when the handler is receiving a text message).
Positional parameters are handled in order, and the return values are converted into TwilML.
For instance, if you return a string from a function, Twilio will read it with the Say
verb. If that string starts with http, Twilio will Play it with the Play verb
. If the result could be XML, it will return the result inside of the TwilML.