pub const X_DNS_PREFETCH_CONTROL: HeaderName;
Controls DNS prefetching.
x-dns-prefetch-control HTTP response header controls DNS
prefetching, a feature by which browsers proactively perform domain name
resolution on both links that the user may choose to follow as well as
URLs for items referenced by the document, including images, CSS,
This prefetching is performed in the background, so that the DNS is likely to have been resolved by the time the referenced items are needed. This reduces latency when the user clicks a link.