[STL]How to increase the quantity of latency streams

[beetyi]

Hi,
To simulate the app traffic and get lossrate, more than 128 streams with same pg_id are used to bulid the traffic curve(dynamic pps、dynamic pkt_len).

Now I want to get the latency. So when building the STLStream object, I change flow_stats from STLFlowStats to STLFlowLatencyStats.
There's a error :
"For payload rules: Can't have two streams with same pg_id, or same stream on more than one port"

How to increase the quantity of latency streams?
Or remove the limit of differnet streams with same pg_id?