title: Merging 2 dictionaries having duplicate keys with linq
body: <p>How to merge 2 dictionaries of <code>IDictionary&lt;Guid, MyObject&gt;</code> where <code>MyObject</code> is a class instance?</p>
  
  <pre><code>IDictionary&lt;Guid, MyObject&gt; d1 = new Dictionary&lt;Guid, MyObject&gt;();
  d1.Add(guid1, m1);
  d1.Add(guid2, m2);
  d1.Add(guid3, m3);
  IDictionary&lt;Guid, MyObject&gt; d2 = new Dictionary&lt;Guid, MyObject&gt;();
  d2.Add(guid2, m2);
  d2.Add(guid3, m3);
  d2.Add(guid4, m4);
  IDictionary&lt;Guid, MyObject&gt; d3 = d1.Union(d2) ???
  </code></pre>
  
  <p>That in <code>d3</code> there are the following entries:</p>
  
  <pre><code>guid1,m1
  guid2,m2
  guid3,m3
  guid4,m4
  </code></pre>