datetime A timestamp in one of the following formats: if the format is omitted or set to rfc3339, uses the "date-time" notation
of RFC3339; if format is set to rfc2616, uses the format defined in RFC2616.
example: 2016-02-28T16:41:41.090Z
format: rfc3339 # the default, so no need to specify
example: Sun, 28 Feb 2016 16:41:41 GMT
format: rfc2616 # this time it's required, otherwise, the example format is invalid
datetime A timestamp in one of the following formats: if the format is omitted or set to rfc3339, uses the "date-time" notation of RFC3339; if format is set to rfc2616, uses the format defined in RFC2616.
example: 2016-02-28T16:41:41.090Z format: rfc3339 # the default, so no need to specify
example: Sun, 28 Feb 2016 16:41:41 GMT format: rfc2616 # this time it's required, otherwise, the example format is invalid