input: [Attribute] ReadTimestamp [Writeable] Yes [Required] No [Description] The time when the message was read by the current user. If null, the message has not been read. [Data Type] 
output: Timestamp
options: C h a r a c t e r
options: T i m e s t a m p
options: B o o l e a n
options: C h a r a c t e r L i s t
options: E x p a n s i o n