The identifier for the event to track. Best practice is to track generic events useful for segmenting, instead of specific user actions (i.e. track watched_sports_video instead of watched_video_adrian_peterson_td_mnf). Value is limited to 255 characters in length, cannot begin with a $, and can only contain alphanumeric characters and punctuation.
OptionaleventProperties: object | nullHash of properties for this event. Keys are limited to 255 characters in length, cannot begin with a $, and can only contain alphanumeric characters and punctuation. Values can be numeric, boolean, or strings 255 characters or shorter.
Reports that the current user performed a custom named event.