Returns a list of employee IDs that have changed since the given timestamp. This allows for efficient syncing of employee data — rather than downloading all employees, only those that have changed are returned. A change in ANY individual field in the employee record, as well as any change to the employment status, job info, or compensation tables, will cause that employee to be returned. Each entry includes the employee ID, the type of change (Inserted, Updated, or Deleted), and the last-changed timestamp.