title: ConcurrentHashMap doesn't work as expected when use byte array as key in Xamarin
body: <p>Here is code block I use in Xamarin Android.</p>
  
  <pre><code>Java.Util.Concurrent.ConcurrentHashMap map = new Java.Util.Concurrent.ConcurrentHashMap();
  var key = new byte[] { 1, 2, 3 };
  var data = new byte[] { 1, 2, 3, 4, 5 };
  
  map.Put(key, data);
  var val = map.Get(key); // null, WHY?
  
  IEnumeration keys = map.Keys();
  while (keys.HasMoreElements)
  {
      var k = keys.NextElement();
      var val2 = map.Get(k); // NOT null, val2 is byte array of {1,2,3,4,5}
  }
  </code></pre>
  
  <p>I expected <code>val</code> is byte array (data), but <code>val</code> is null, while <code>val2</code> is not null.</p>
  
  <p>But this Java code works very well.</p>
  
  <pre><code>java.util.concurrent.ConcurrentHashMap map = new java.util.concurrent.ConcurrentHashMap();
  
  byte[] key = {1, 2, 3};
  byte[] data = {1, 2, 3, 4, 5};
  
  map.put(key, data);
  Object o = map.get(key); // byte array of {1,2,3,4,5}
  </code></pre>
  
  <p>What is the reason?</p>