title: Qpid Proton: idle_timeout configuration
body: <p>I am using Qpid Proron 0.18.1 version. The idle_timeout is printing out to be, 
  <code>connection.idle_timeout() : 15000</code>. I am not able to trace back to the code where the default value <code>15000</code> is set. Also, when I am changing it in container as follows:</p>
  
  <pre><code>c.connect(conn_url, co.idle_timeout(proton::duration::FOREVER));
  </code></pre>
  
  <p>This is making the broker time out after a minute. However,</p>
  
  <pre><code>c.connect(conn_url, co.idle_timeout(proton::duration::SECOND));
  </code></pre>
  
  <p>is not making the broker timeout at all even though I thought that this should timeout after a second of the broker being idle.</p>
  
  <p>It would be great if someone can explain me about <code>idle_timeout()</code> and if there is a possibility to change its default value.</p>
  
  <p>Thanks!</p>