title: Include header only once at the top of a rolling file
body: <p>Is it possible to only include header information at the top of a rolling file?</p>
  
  <p>I have the following config file:</p>
  
  <pre><code>&lt;appender name="RollingFileAppender" type="log4net.Appender.RollingFileAppender"&gt;
              &lt;file value="d:\temp\TTTest.log"/&gt;
              &lt;layout type="log4net.Layout.PatternLayout"&gt;
                  &lt;header value="[Header]&amp;#13;&amp;#10;" /&gt;
                  &lt;param name="ConversionPattern" value="%-25utcdate{dd/MM/yyyy HH:mm:ss.fff}%-20property{log4net:HostName}%-30logger%-30thread%-7level%message%newline"/&gt;
              &lt;/layout&gt;
              &lt;lockingModel type="log4net.Appender.FileAppender+MinimalLock"/&gt;
              &lt;maximumFileSize value="5MB"/&gt;
              &lt;rollingStyle value="Size"/&gt;
              &lt;maxSizeRollBackups value="-1"/&gt;
              &lt;countDirection value="1"/&gt;
          &lt;/appender&gt;
  </code></pre>
  
  <p>When I run my application, for example twice I get header information twice e.g.</p>
  
  <pre><code> [Header] 
   The Log line
   [Header]
   The Log line 
   etc
  </code></pre>
  
  <p>I am looking to achieve the following:</p>
  
  <pre><code> [Header] 
   The Log line
   The Log line 
   etc
  </code></pre>