title: Concat fixed number of Optionals to Stream
body: <p>I have 3 Optionals:</p>
  <pre><code>Optional&lt;T&gt; optA = getOptA();
  Optional&lt;T&gt; optB = getOptB();
  Optional&lt;T&gt; optC = getOptC();
  </code></pre>
  <p>Is there a better way to concat them to a <code>Stream&lt;T&gt;</code> than:</p>
  <pre><code>Stream.concat(Stream.concat(optA.stream(), optB.stream()), optC.stream());
  </code></pre>
  <p>If the number of optionals grows, this gets unwieldy very soon:</p>
  <pre><code>Stream.concat(Stream.concat(optA.stream(), optB.stream()), Stream.concat(optC.stream(), optD.stream());
  </code></pre>