def to_pipeline
      pipeline = []
      pipeline.push({ "$skip" => skip }) if skip
      pipeline.push({ "$limit" => limit }) if limit
      pipeline.push({ "$sort" => sort }) if sort
      pipeline
    end
def to_pipeline
      pipeline = []
      pipeline.push({ "$skip" => skip }) if skip
      pipeline.push({ "$limit" => limit }) if limit
      pipeline.push({ "$sort" => sort }) if sort
      pipeline
    end
Convert the options to aggregation pipeline friendly options.

 @example Convert the options to a pipeline.
   options.to_pipeline

 @return [ Array<Hash> ] The options in pipeline form.

 @since 2.0.0