protected String getLoadTestMark(SofaTracerSpan span) {
        if (TracerUtils.isLoadTest(span)) {
            return "T";
        } else {
            return "F";
        }
    }
Get zone

@param tagsWithStr tags
@return zone
tracer/tracer-opentracing/src/main/java/com/alipay/sofa/rpc/tracer/sofatracer/log/stat/AbstractRpcStatJsonReporter.java