code: function toNodeStream (renderer) {
    let sourceIsReady = true;
  
    const read = () => {
      // If source is not ready, defer any reads until the promise resolves.
      if (!sourceIsReady) { return false; }
  
      sourceIsReady = false;
      const pull = pullBatch(renderer, stream);
  
      return pull.then(result => {
        sourceIsReady = true;
        if (result === EXHAUSTED) {
          return stream.push(null);
        } else {
          if (result !== INCOMPLETE) {
            stream.push(result);
          }
          return read();
        }
      }).catch(err => {
        return stream.emit("error", err);
      });
    };
  
    const stream = new Readable({ read });
  
    return stream;
  }
docs: Consumes the provided sequence and pushes onto a readable Node stream.
  
  @param      {Renderer}  renderer        The Renderer from which to pull next-vals.
  
  @return     {Readable}                  A readable Node stream.