Required. The parent catalog name, such as
Required. URL encoded UserEvent proto with a
length limit of 2,000,000 characters.
The URL including cgi-parameters but
excluding the hash fragment with a length limit
of 5,000 characters. This is often more useful
than the referer URL, because many browsers only
send the domain for 3rd party requests.
The event timestamp in milliseconds. This
prevents browser caching of otherwise identical
get requests. The name is abbreviated to reduce
the payload bytes.