@Override
  public ByteRange get(int index, byte[] dst, int offset, int length) {
    if (0 == length) {
      return this;
    }

    System.arraycopy(this.bytes, this.offset + index, dst, offset, length);
    return this;
  }
Returns true when {@code range} is of zero length, false otherwise.
hbase-common/src/main/java/org/apache/hadoop/hbase/util/AbstractByteRange.java