title: C# Array Merge Without Dupes
body: <p>Let's say I have these two arrays:</p>
  
  <pre><code>string[] arr1 = new string[2]{"Hello", "Stack"}
  string[] arr2 = new string[2]{"Stack", "Overflow"}
  </code></pre>
  
  <p>How would I merge them to get a third array like so: <code>string[3]{"Hello", "Stack", "Overflow"}</code>?</p>