public Gauge gauge(long value, String name, MetricLevel metricLevel, String... tags) {
    Gauge gauge = getOrCreateGauge(name, metricLevel, tags);
    gauge.set(value);
    return gauge;
  }
Set value of gauge. if exists, then set gauge by value. if not, then create and set.

@param value the value of gauge
@param name the name of name
@param metricLevel the level of name
@param tags string pairs, like sg="ln" will be "sg", "ln"
iotdb-core/metrics/interface/src/main/java/org/apache/iotdb/metrics/AbstractMetricManager.java