[minor] Added body decoder middleware example. Needs fixing.

examples/body-decoder.js

+#!/usr/local/bin/node
+
+var httpProxy = require('http-proxy'),
+    http = require('http'),
+    util = require('util'),
+    colors = require('colors');
+
+
+exports.bodyMod = function () {
+  console.log('middleware has been started.'.green);
+  return function (req, res, next) {
+    var proxy = next,
+        total = '';
+
+    req.on('data', function (data) {
+      console.log('ON DATA')
+      total += data;
+    });
+    req.on('end', function () {
+      console.log('ON END')
+      console.log(total);
+      // This line, uncommented, hangs forever.
+      // proxy.proxyRequest(req, res, { port: 9000, host: 'localhost' });
+      // The following also hangs forever.
+      // next.proxyRequest(req, res, { port: 9000, host: 'localhost' });
+    })
+    // The following fires just fine.
+    //proxy.proxyRequest(req, res, { port: 9000, host: 'localhost' });
+    console.log('request proxied...'.blue); 
+  }
+}
+
+var proxyServer = httpProxy.createServer(
+  // Your middleware stack goes here.  
+  exports.bodyMod()
+).listen(8000);
+
+
+var httpServer = http.createServer(function (req, res) {
+  res.writeHead(200, { 'Content-Type': 'text/plain' });
+  res.write('request successfully proxied to: ' + req.url + '\n' + JSON.stringify(req.headers, true, 2));
+  res.end();
+}).listen(9000);
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