mylog1.xml

<PropertyList>
  <logging>
    <log n="0">
      <enabled type="bool">true</enabled>
      <interval-ms type="long">50</interval-ms>
      <filename>fg_log.txt</filename>
      <delimiter> </delimiter>
      <entry n="0">
        <enabled type="bool">true</enabled>
        <title>frameSpacing</title>
        <property>/sim/frame-latency-max-ms</property>
      </entry>
      <entry n="1">
        <enabled type="bool">true</enabled>
        <title>actualFPS</title>
        <property>/sim/frame-rate</property>
      </entry>
    </log>
  </logging>
</PropertyList>