Add benchmark vs naked bunyan

package.json

@@ -19,6 +19,7 @@
   "main": "dist/node.js",
   "browser": "dist/client.js",
   "scripts": {
+    "benchmark": "node test/benchmark",
     "test": "npm run test:browser && npm run test:node && npm run test:leakage",
     "tdd": "npm-run-all --parallel test:*:tdd",
     "test:ci": "npm run test:browser && npm run test:node:ci",
@@ -87,6 +88,7 @@
     "babel-polyfill": "6.20.0",
     "babel-preset-es2015": "6.18.0",
     "babel-preset-stage-0": "6.16.0",
+    "benchmark": "2.1.3",
     "chai": "3.5.0",
     "coveralls": "2.11.15",
     "documentation": "4.0.0-beta11",

test/benchmark/index.js

@@ -0,0 +1,35 @@
+/* eslint-disable no-console */
+
+const Benchmark = require('benchmark')
+const bunyan = require('bunyan');
+const WeLogger = require('../..');
+
+var suite = new Benchmark.Suite();
+
+const weLogger = new WeLogger({ stdout: false });
+const bunyanLogger = bunyan.createLogger({ name: 'bunyan', streams: [] });
+
+suite
+  .add('we-js-logger', function() {
+    weLogger.info('hello world')
+  })
+  .add('we-js-logger child', function() {
+    const log = weLogger.child();
+    log.info('hello world');
+  })
+  .add('bunyan', function() {
+    bunyanLogger.info('hello world');
+  })
+  .add('bunyan child', function() {
+    const log = bunyanLogger.child();
+    log.info('hello world');
+  })
+  // add listeners
+  .on('cycle', function(event) {
+    console.log(String(event.target));
+  })
+  .on('complete', function() {
+    console.log('Fastest is ' + this.filter('fastest').map('name'));
+  })
+  // run async
+  .run({ 'async': true });