public long load(final Upstream upstream) {
        long lag = (long) (Math.sqrt((double) upstream.getLag()) + 1);
        long load = lag * upstream.getInflight().get();
        if (load == 0) {
            load = PENALTY;
        }
        return load;
    }
calculate load.

@param upstream the upstream
@return load
shenyu-loadbalancer/src/main/java/org/apache/shenyu/loadbalancer/spi/P2cLoadBalancer.java