HTTP Server request.setTimeout(n, cb) does sometimes call socket.destroy(), contradicting documentation

test-http-server-request-settimeout-destroy.js

var http = require('http');

var mode;
mode = 'requestTimeout';
// mode = 'responseTimeout';
// mode = 'serverTimeout';
// mode = 'serverTimeoutExternal';

var timeout = 100;

var port = 3000;


console.log('Test HTTP Server with timeout on Server, Request, Response & socket destroy: unexpected destroy on req.setTimeout(n, cb);');

var server = http.createServer(function(req, res) {
  console.log('server', 'got request');

  if (mode === 'requestTimeout') {
    req.setTimeout(timeout, function() {
      console.log('server', 'request timeout');
      res.end('server hello from request timeout');
    });
  }

  if (mode === 'responseTimeout') {
    res.setTimeout(timeout, function() {
      console.log('server', 'request timeout');
      res.end('server hello from request timeout');
    });
  }

  if (mode === 'serverTimeout' || mode === 'serverTimeoutExternal') {
    server.setTimeout(timeout, function() {
      console.log('server', 'request timeout');
      res.end('server hello from request timeout');
    });
  }

}).listen(port, function() {

  console.log('client', 'sending request');
  var req = http.request({port: port}, function(res) {
    console.log('client', 'got response');
    res.on('data', function (chunk) {
      console.log('client', 'reponse', 'data:', chunk.toString());
    });
    res.on('finish', function () {
      console.log('client', 'response', 'finish');
    });
  });

  req.on('error', function(e) {
    console.log('client', 'error', e);
  });

  req.end();
});

if (mode === 'serverTimeoutExternal') {
  server.setTimeout(timeout);
}

// cleanup
setTimeout(function() {
  console.log('exit');
  process.exit();
}, timeout + 100);


/** Results:
 * same results for the following node versions: v0.10.41, v0.12.9, v4.2.3, v5.2.0

 ** mode RequestTimeout
client sending request
server got request
client error { [Error: socket hang up] code: 'ECONNRESET' }  <-- unexpected

 ** mode ResponseTimeout
client sending request
server got request
server request timeout
client got response
client reponse data: server hello from request timeout

 ** mode ServerTimeout
client sending request
server got request

 ** mode ServerTimeoutExternal
client sending request
server got request
server request timeout
client got response
client reponse data: server hello from request timeout
 **/