public void clear() {
    this.buf = null;
    this.offset = 0;
    this.length = 0;
    this.rowLen = 0;
  }
Completely clears the state of this cell. Useful if you want to reuse this object to avoid
allocations.
hbase-common/src/main/java/org/apache/hadoop/hbase/ByteBufferKeyOnlyKeyValue.java