node v6.x 不支持 async await 吗？

node版本是 v6.2.2

新建一个 app.js 内容如下

async function responseTime(ctx, next) {
  const start = new Date();
  await next();
  const ms = new Date() - start;
  ctx.set('X-Response-Time', `${ms}ms`);
然后node app.js报如下错误：
mbp:hybrid-statistic wfp$ node app.js
/Users/wfp/Work/hybrid-statistic/app.js:28
async function responseTime(ctx, next) {
      ^^^^^^^^
SyntaxError: Unexpected token function
    at Object.exports.runInThisContext (vm.js:53:16)
    at Module._compile (module.js:513:28)
    at Object.Module._extensions..js (module.js:550:10)
    at Module.load (module.js:458:32)
    at tryModuleLoad (module.js:417:12)
    at Function.Module._load (module.js:409:3)