title: Autofixture customizations: provide constructor parameter
body: <p>I have the following class:</p>
  
  <pre><code>class Foo
  {
      public Foo(string str, int i, bool b, DateTime d, string str2)
      {
           .....
      }
  }
  </code></pre>
  
  <p>I'm creating a <code>Foo</code> with AutoFixture:</p>
  
  <pre><code>var foo = fixture.Create&lt;Foo&gt;();
  </code></pre>
  
  <p>but I want AutoFixture to provide a known value for the <code>str2</code> parameter and use the default behavior for every other parameter.</p>
  
  <p>I tried implementing a <code>SpecimenBuilder</code> but I can't find a way to get the metadata associated with the request to know that I'm being called from the Foo constructor.</p>
  
  <p>Is there any way to achieve this?</p>