code: @Deprecated
    public void push(Collector collector, String job, String instance) throws IOException {
      push(collector, job, Collections.singletonMap("instance", instance));
    }
docs: Pushes all metrics in a Collector, replacing all those with the same job and instance.
  <p>
  This is useful for pushing a single Gauge.
  <p>
  This uses the PUT HTTP method.
  @deprecated use {@link #push(Collector, String, Map)}