<rewrite>
    <rules>
        <rule name="CDN: fonts" stopProcessing="true">
            <match url="^fonts/(.*)" />
            <action type="Rewrite" url="http://cdn.staging.mysite.net/fonts/{R:1}" appendQueryString="true" />
        </rule>
        <rule name="CDN: images" stopProcessing="true">
            <match url="^images/(.*)" />
            <action type="Rewrite" url="http://cdn.staging.mysite.net/images/{R:1}" appendQueryString="true" />
        </rule>
        <rule name="CDN: pdf" stopProcessing="true">
            <match url="^pdf/(.*)" />
            <action type="Rewrite" url="http://cdn.staging.mysite.net/pdf/{R:1}" appendQueryString="true" />
        </rule>
        <rule name="CDN: scripts" stopProcessing="true">
            <match url="^scripts/(.*)" />
            <action type="Rewrite" url="http://cdn.staging.mysite.net/scripts/{R:1}" appendQueryString="true" />
        </rule>
        <rule name="CDN: style" stopProcessing="true">
            <match url="^style/(.*)" />
            <action type="Rewrite" url="http://cdn.staging.mysite.net/style/{R:1}" appendQueryString="true" />
        </rule>
    </rules>
</rewrite>

<rewrite>
  <rules>
    <rule name="Rewrite to CDN">
      <match url="^assets/(.+)$" />
      <action type="Rewrite" url="http://cdn.domain.com/{R:0}" />
    </rule>
   </rules>
</rewrite>