This is a direct port of EventEmitter3 to es2015. It passes the tests exactly (see Caveats below).
This aims to be a drop in replacement for 99% of use cases.
Because we are now using a class instead of a prototype, util.inherits now does not work. If you find a solution to this, please file a pull request.
Similarly because we are now exporting a class, the exported object is slightly different. It now does not contain proxies for
allow usage with