如何让log4net csv日志记录只创建一个标头

<configuration>
  <configSections>
    <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net" />
  </configSections>
  
  <log4net>
    <!-- log4net配置 -->
  </log4net>
  
  <!-- 其他配置 -->
</configuration>

<log4net>
  <appender name="CsvAppender" type="log4net.Appender.FileAppender">
    <file value="logs\log.csv" />
    <appendToFile value="true" />
    <lockingModel type="log4net.Appender.FileAppender+MinimalLock" />
    <layout type="log4net.Layout.PatternLayout">
      <conversionPattern value="%message%newline" />
    </layout>
  </appender>
  
  <root>
    <level value="DEBUG" />
    <appender-ref ref="CsvAppender" />
  </root>
</log4net>

private static readonly log4net.ILog log = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);

log.Debug("This is a debug message.");
log.Info("This is an info message.");
log.Error("This is an error message.");