MatrixStatsMode
The matrix_stats aggregation treats each document field as an independent sample.
The mode parameter controls what array value the aggregation will use for array or
multi-valued fields.
Avg = 0
(default) Use the average of all values.
Max = 2
Pick the highest value.
Median = 4
Use the median of all values.
Min = 1
Pick the lowest value.
Sum = 3
Use the sum of all values.