addition of example for threading via net server

Addition of working example demonstrating threading via clustering and a net server forwarding socket connections to ldapjs.

examples/cluster-threading-net-server.js

@@ -0,0 +1,66 @@
+const cluster = require('cluster');
+const ldap = require('ldapjs');
+const net = require('net');
+const os = require('os');
+
+const threads = [];
+threads.getNext = function () {
+    return (Math.floor(Math.random() * this.length));
+};
+
+const serverOptions = {
+    port: 1389
+};
+
+if (cluster.isMaster) {
+    const server = net.createServer(serverOptions, (socket) => {
+        socket.pause();
+        console.log('ldapjs client requesting connection');
+        let routeTo = threads.getNext();
+        threads[routeTo].send({ type: 'connection' }, socket);
+    });
+
+    for (let i = 0; i < os.cpus().length; i++) {
+        let thread = cluster.fork({
+            'id': i
+        });
+        thread.id = i;
+        thread.on('message', function (msg) {
+
+        });
+        threads.push(thread);
+    }
+
+    server.listen(serverOptions.port, function () {
+        console.log('ldapjs listening at ldap://127.0.0.1:' + serverOptions.port);
+    });
+} else {
+    const server = ldap.createServer(serverOptions);
+
+    let threadId = process.env.id;
+
+    process.on('message', (msg, socket) => {
+        switch (msg.type) {
+            case 'connection':
+                server.newConnection(socket);
+                socket.resume();
+                console.log('ldapjs client connection accepted on ' + threadId.toString());
+        }
+    });
+
+    server.search('dc=example', function (req, res, next) {
+        console.log('ldapjs search initiated on ' + threadId.toString());
+        var obj = {
+            dn: req.dn.toString(),
+            attributes: {
+                objectclass: ['organization', 'top'],
+                o: 'example'
+            }
+        };
+
+        if (req.filter.matches(obj.attributes))
+            res.send(obj);
+
+        res.end();
+    });
+}