code: function handleMasterPayload (payload) {
    // Parse and validate received payload.
    if ((payload = utils.parsePayload(payload)) === null) return
  
    // Notify all workers except the worker who emitted the event.
    sendPayload.call(this, payload)
  }
docs: handleMasterPayload handles the payload recieved by the master process. If
  payload is valid it is echoed back to all workers. Note that unlike the
  handleWorkerPayload the listeners of the instance won't be notified.
  @param  {String} payload Payload received from a worker.