You should probably not be calling this function from “normal” code
(since you should already know what keys are in your schema). This
function is intended for introspection reasons.
Available since: 2.46
Return value
Type: An array of utf8
A list
of the keys on schema, in no defined order.
The array is NULL-terminated.
The caller of the method takes ownership of the data, and is responsible for freeing it.