This value type is used to identify properties that contain a calendar user address.
This value type is defined by the following notation:
cal-address = uri
The value is a URI as defined by [RFC3986] or any other IANA-registered form for a URI. When used to address an Internet email transport address for a calendar user, the value MUST be a mailto URI, as defined by [RFC2368]. No additional content value encoding (i.e., BACKSLASH character encoding, see Section 3.3.11) is defined for this value type.