post https://{region}.mixpanel.com/engage#profile-batch-update
Send a batch of profile updates. Instead of sending a single JSON object as the data query parameter, send a JSON list of objects as the data parameter of an application/json POST or GET request body.
Refer to the respective user profile update commands ($set, $set_once, $add, $union, $append, $remove, $unset, and $delete) on syntax for their parameters.