public override IAggregateFluent <AggregateBucketAutoResult <TValue> > BucketAuto <TValue>(
     AggregateExpressionDefinition <TResult, TValue> groupBy,
     int buckets,
     AggregateBucketAutoOptions options = null)
 {
     return(WithPipeline(_pipeline.BucketAuto(groupBy, buckets, options)));
 }