Get an inventory bit vector for the zonefiles in the
        given bit range (i.e. offset and length are in bytes)
        Returns at most 64k of inventory (or 524288 bits)
        Return {'status': True, 'inv': ...} on success, where 'inv' is a b64-encoded bit vector string
        Return {'error': ...} on error.

def rpc_get_zonefile_inventory( self, offset, length, **con_info ):
        """
        Get an inventory bit vector for the zonefiles in the
        given bit range (i.e. offset and length are in bytes)
        Returns at most 64k of inventory (or 524288 bits)
        Return {'status': True, 'inv': ...} on success, where 'inv' is a b64-encoded bit vector string
        Return {'error': ...} on error.
        """
        conf = get_blockstack_opts()
        if not is_atlas_enabled(conf):
            return {'error': 'Not an atlas node', 'http_status': 400}

        if not check_offset(offset):
            return {'error': 'invalid offset', 'http_status': 400}

        if not check_count(length, 524288):
            return {'error': 'invalid length', 'http_status': 400}

        zonefile_inv = atlas_get_zonefile_inventory( offset=offset, length=length )

        if BLOCKSTACK_TEST:
            log.debug("Zonefile inventory is '%s'" % (atlas_inventory_to_string(zonefile_inv)))

        return self.success_response( {'inv': base64.b64encode(zonefile_inv) } )