{
  "optimize": "size",
  "allowedStartRules": [
     "Contact",
     "Name_Addr_Header",
     "Record_Route",
     "Request_Response",
     "SIP_URI",
     "Subscription_State",
     "Supported",
     "Require",
     "Via",
     "absoluteURI",
     "Call_ID",
     "Content_Disposition",
     "Content_Length",
     "Content_Type",
     "CSeq",
     "displayName",
     "Event",
     "From",
     "host",
     "Max_Forwards",
     "Min_SE",
     "Proxy_Authenticate",
     "quoted_string",
     "Refer_To",
     "Replaces",
     "Session_Expires",
     "stun_URI",
     "To",
     "turn_URI",
     "uuid",
     "WWW_Authenticate",
     "challenge"
  ]
}