2.1.3.1.1.20.12 Property: DURATION
RFC Reference: [RFC2445] section 4.8.2.5
Number of Instances Allowed: 0, 1
Format: Duration ([RFC2445] section 4.3.6)
Brief Description: Specifies the duration of an appointment.
Importing to Calendar objects
If only one of DTSTART and DTEND is present, the DURATION property SHOULD<155> be used to compute the missing property.
Exporting from Calendar objects
This parameter SHOULD NOT be exported.