Returns a list of users that were registered by the current partner.
- The parameter 'externalId' lets you select a user based on the external ID.
- The parameter 'offset' lets you choose the starting point of the query, e.g. say there are 10 users, then offset = 5 will get you users 5 to 10.
- The parameter 'count' lets you choose the number of users to return. By default it is set to 100.