code: function sendPayload (payload) {
    // Marshal args.
    payload[fields.args] = marshaller.marshal(payload[fields.args])
  
    // Go through each worker and send them the payload.
    this.__workers.forEach((worker) => {
      const pidKey = fields.pid
      // If payload originates from a worker being traversed, don't echo the
      // payload back to it.
      if (payload[pidKey] !== undefined && payload[pidKey] === worker.pid) return
      worker.send(payload)
    })
  }
docs: sendPayload sends a payload to all the acknowledged workers. Note that if the
  payload originated from a worker (payload would have the 'pid' field), the
  payload isn't sent to the worker it originated from.
  @param  {Number}       payload.IPCE_pid   The process id of the worker which
  the payload originated from. Note
  that if the payload is sent from
  the master, this field will not be
  present.
  @param  {String}       payload.IPCE_event The name of the emitted event.
  @param  {Array{Mixed}} payload.IPCE_args  Arguments to be provided to the
  listeners of the emitted event.