def METHOD_NAME(self):
    sio = io.BytesIO()
    flt = flowfilter.parse("~c 200")
    w = mitmproxy.io.FilteredFlowWriter(sio, flt)
    f = tflow.tflow(resp=True)
    f.response.status_code = 200
    w.add(f)
    f = tflow.tflow(resp=True)
    f.response.status_code = 201
    w.add(f)
    sio.seek(0)
    r = mitmproxy.io.FlowReader(sio)
    assert len(list(r.stream()))