All event's attributes.
Event label. Must be a string, will automatically be bridged as label for application event compatibility. Must not be longer than 200 characters
Event tags. Must be an array of string, will automatically be bridged as tags for application event compatibility. Strings must not be longer than 64 characters and array must not be longer than 10 items.
Event data attribute type
Some event attributes have reserved keys, and are all prefixed by a $ sign. This is the list of currently reserved event attributes. You cannot set an event attribute starting by a $ sign.