Update implementation.html (#10771)

Fixing the link to a cited blog. The existing link now points to a steroid website so need to pull the blog from internet archives.

docs/implementation.html

@@ -18,7 +18,7 @@
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     <h3 class="anchor-heading"><a id="networklayer" class="anchor-link"></a><a href="#networklayer">5.1 Network Layer</a></h3>
     <p>
-    The network layer is a fairly straight-forward NIO server, and will not be described in great detail. The sendfile implementation is done by giving the <code>MessageSet</code> interface a <code>writeTo</code> method. This allows the file-backed message set to use the more efficient <code>transferTo</code> implementation instead of an in-process buffered write. The threading model is a single acceptor thread and <i>N</i> processor threads which handle a fixed number of connections each. This design has been pretty thoroughly tested <a href="http://sna-projects.com/blog/2009/08/introducing-the-nio-socketserver-implementation">elsewhere</a> and found to be simple to implement and fast. The protocol is kept quite simple to allow for future implementation of clients in other languages.
+    The network layer is a fairly straight-forward NIO server, and will not be described in great detail. The sendfile implementation is done by giving the <code>MessageSet</code> interface a <code>writeTo</code> method. This allows the file-backed message set to use the more efficient <code>transferTo</code> implementation instead of an in-process buffered write. The threading model is a single acceptor thread and <i>N</i> processor threads which handle a fixed number of connections each. This design has been pretty thoroughly tested <a href="https://web.archive.org/web/20120619234320/http://sna-projects.com/blog/2009/08/introducing-the-nio-socketserver-implementation/">elsewhere</a> and found to be simple to implement and fast. The protocol is kept quite simple to allow for future implementation of clients in other languages.
     </p>
     <h3 class="anchor-heading"><a id="messages" class="anchor-link"></a><a href="#messages">5.2 Messages</a></h3>
     <p>