title: Counter with tags - How to group by dimension/tag?
body: <p>I am trying to understand spring micromenter's group by dimension/tag functionality. I am using StepMeterRegistry and incrementing the counter but don't see desired result.</p>
  
  <p>create counters as,</p>
  
  <pre><code>final MeterRegistry myRegistry = new StepMeterRegistry(config, Clock.SYSTEM) {...};
  
  final Counter myCounter1 = myRegistry.counter("myTestCounter", "tag1", "value1");
  final Counter myCounter2 = myRegistry.counter("myTestCounter", "tag2", "value2");
  final Counter myCounter1n2 = myRegistry.counter("myTestCounter", "tag1", "value1", "tag2", "value2");
  </code></pre>
  
  <p>increment counters as,</p>
  
  <pre><code>myCounter1.increment();
  myCounter2.increment();
  myCounter1n2.increment();
  </code></pre>
  
  <p>when i print (after step duration),</p>
  
  <pre><code>myCounter1.measure(); =&gt; value=1.0
  myCounter2.measure(); =&gt; value=1.0
  myCounter1n2.measure(); =&gt; value=1.0
  </code></pre>
  
  <p>whereas i was expecting (after step duration),</p>
  
  <pre><code>myCounter1.measure(); =&gt; value=2.0
  myCounter2.measure(); =&gt; value=2.0
  myCounter1n2.measure(); =&gt; value=1.0
  </code></pre>
  
  <p>Is my understanding correct ? Or how can i realize group by (or) select by functionality ?</p>