message: Fix Node.js 4 support
diff: @@ -17,6 +17,10 @@ const BLACKLIST = new Set(['env', 'mainModule', '_events']);
  // mimic it (see https://nodejs.org/api/process.html#process_process_env).
  function createProcessEnv() {
  + if (typeof Proxy === 'undefined') {
  + return deepCyclicCopy(process.env);
  + }
  +
  // $FlowFixMe: Apparently Flow does not understand that this is a prototype.
  const proto: Object = Object.getPrototypeOf(process.env);
  const real = Object.create(proto);
  