docs: function Writer(options) {
    options = merge(DEFAULT_OPTS, options || {});
  
    this._buf = Buffer.alloc(options.size || 1024);
    this._size = this._buf.length;
    this._offset = 0;
    this._options = options;
  
    // A list of offsets in the buffer where we need to insert
    // sequence tag/len pairs.
    this._seq = [];
  }