code: function(tagName) {
      var parentBuffer = get(this, 'parentBuffer');
  
      return this.newBuffer(tagName, parentBuffer, function(buffer) {
        var siblings = parentBuffer.childBuffers;
        var index = indexOf.call(siblings, this);
        siblings.splice(index + 1, 0, buffer);
      });
    }
docs: Insert a new render buffer after the current render buffer.
  
  @param {String} tagName Tag name to use for the new buffer's element