<p>Content Distribution Networks (CDNs) such as <a href="http://aws.amazon.com/cloudfront/">Amazon CloudFront</a> and
<a href="http://www.fastly.com/">Fastly</a> have the ability to “pull” content from their <a href="http://www.w3.org/Protocols/rfc2616/rfc2616-sec1.html#sec1.3">origin server</a>
during HTTP requests in order to cache them. They can also proxy POST, PUT,
PATCH, DELETE, and OPTION HTTP requests…</p>

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