Get a list of suburbs/cities/towns. 

By default, it will return a complete list of all suburbs. This is more than 16,000 records. To narrow down the list, specify a state and/or since date. 

If a state is specified, only suburbs belonging to that state/territory will be returned. 

If a sinceDate is specified, only suburbs that have been created or modified since that date will be returned. 

Returns a list of suburbs, each one represented by a TSuburb object. 

A token is passed for authentication. If the authentication fails, or other errors occur, the suburbs are not returned. The result of the authentication is represented by a TAuthenticate object. 

This function has security level "Unrestricted", and can be accessed by any authenticated user.

[WebMethod(Description = "Gets a list of suburbs, optionally for a state and/or that have been modified since a date")]
public TAuthSuburbList GetSuburbList(string token, string state, DateTime? sinceDate);