public static long getKeyDataStructureSize(int rlength, int flength, int qlength) {
    return (long) KeyValue.KEY_INFRASTRUCTURE_SIZE + rlength + flength + qlength;
  }
Computes the number of bytes that a <code>KeyValue</code> instance with the provided
characteristics would take up in its underlying data structure for the key.
@param rlength row length
@param flength family length
@param qlength qualifier length
@return the key data structure length
hbase-common/src/main/java/org/apache/hadoop/hbase/KeyValue.java