fe7c9e08_oice__VoIP__and_Text_Messaging__Description
[Property] RequestVariables [Description] 
The Twilio-generated HTTP GET or POST variables sent to your server. Alternatively, if the notification was generated by the REST API, this field will include any HTTP POST or PUT variables you sent to the REST API.
Twilio Cloud Communications - APIs for Voice, VoIP, and Text Messaging