public void setUpstreamHost(final String upstreamHost) {
        this.upstreamHost = upstreamHost;
    }
set host of a upstream.
@param upstreamHost upstreamHost
shenyu-e2e/shenyu-e2e-common/src/main/java/org/apache/shenyu/e2e/model/handle/DivideUpstream.java