Histogram getHistogram() {
      return histogram;
    }
Holds a Histogram and supporting min/max and range buckets for analyzing distribution of key
bytes, value bytes, row bytes, and row columns. Supports adding values, getting the histogram,
and getting counts per range.
hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/HFilePrettyPrinter.java