Document Memcached distributed cache factory

Author: fredericDelaporte

doc/reference/modules/nhibernate_caches.xml

@@ -127,8 +127,9 @@
 						<para>
 							Uses <classname>Microsoft.Extensions.Caching.Abstractions.IDistributedCache</classname> implementations as the cache
 							provider. The implementation has to be provided through an <literal>IDistributedCacheFactory</literal>.
-							Distributed cache factories for <literal>Redis</literal>, <literal>SqlServer</literal> and <literal>Memory</literal>
-							caches are available through their own package, prefixed by <literal>NHibernate.Caches.CoreDistributedCache.</literal>.
+							Distributed cache factories for <literal>Memcached</literal>, <literal>Redis</literal>, <literal>SqlServer</literal>
+							and <literal>Memory</literal> caches are available through their own package, prefixed by
+							<literal>NHibernate.Caches.CoreDistributedCache.</literal>.
 						</para>
 						<para>
 							This provider is available as a .Net Standard NuGet package. See <xref linkend="NHibernate.Caches.CoreDistributedCache" />.
@@ -778,6 +779,49 @@
 			cache has no effects with CoreDistributedCache.
 		</para>
 
+		<section id="NHibernate.Caches.CoreDistributedCache.Memcached">
+			<title>Memcached distributed cache factory</title>
+
+			<para>
+				<literal>NHibernate.Caches.CoreDistributedCache.Memcached</literal> provides a Redis distributed cache factory.
+				This factory yields a <literal>Enyim.Caching.MemcachedClient</literal> from <literal>EnyimMemcachedCore</literal>.
+				For using it, reference the cache factory package and set the <literal>factory-class</literal> attribute of the
+				<literal>coredistributedcache</literal> configuration section to
+				<literal>NHibernate.Caches.CoreDistributedCache.Memcached.MemcachedFactory, NHibernate.Caches.CoreDistributedCache.Memcached</literal>.
+			</para>
+
+			<para>
+				Memcached does not support sliding expirations. <literal>cache.use_sliding_expiration</literal> setting or
+				<literal>sliding</literal> region setting do not have any effect with Memcached.
+			</para>
+
+			<para>
+				The following additional properties can be configured:
+			</para>
+
+			<variablelist>
+				<varlistentry>
+					<term><literal>configuration</literal></term>
+					<listitem>
+						The JSON configuration of <literal>EnyimMemcachedCore</literal>, see its
+						<ulink url="https://github.com/cnblogs/EnyimMemcachedCore">project website</ulink>. It has to be structured
+						like the value part of the <literal>"enyimMemcached"</literal> property in an
+						<literal>appsettings.json</literal> file.
+						<example>
+							<programlisting><![CDATA[{
+  "Servers": [
+    {
+      "Address": "localhost",
+      "Port": 11211
+    }
+  ]
+}]]></programlisting>
+						</example>
+					</listitem>
+				</varlistentry>
+			</variablelist>
+		</section>
+
 		<section id="NHibernate.Caches.CoreDistributedCache.Redis">
 			<title>Redis distributed cache factory</title>