title: how can I get bolt data source?
body: <p>I'm new to storm environment and I have a question! I have 2 spouts (spoutA and spoutB) that emits data to a bolt (bolt1). I defined this bolt in this way: </p>
  
  <pre><code>builder.setBolt("bolt1", bolt1).shuffleGrouping("spoutA").shuffleGrouping("spoutB"); 
  </code></pre>
  
  <p>Is there a way in bolt1 to know for every tuple received what is its source (spoutA or spoutB)?</p>