code: function sendIpc(message) {
      var requestIds;
      clearTimeout(retryTimer);
      if (message) { tranRequests[message._requestId] = message; }
      if ((requestIds = Object.keys(tranRequests)).length) {
        if (!childProc) { throw new Error('Child process already exited.'); }
        requestIds.forEach(function(requestId) {
          console.info('Try to send IPC message: %d', +requestId);
          childProc.send(tranRequests[requestId]);
        });
        retryTimer = setTimeout(errorHandle(sendIpc), IPC_RETRY_INTERVAL);
      }
    }
docs: Recover failed IPC-sending. In some environment, IPC message does not reach to child, with no error and return value.