int getQualifierLength(int keyLength, int rlength, int flength) {
    return keyLength - (int) KeyValue.getKeyDataStructureSize(rlength, flength, 0);
  }
This Cell is an implementation of {@link ByteBufferExtendedCell} where the data resides in off
heap/ on heap ByteBuffer
hbase-common/src/main/java/org/apache/hadoop/hbase/ByteBufferKeyValue.java