@Override
    protected void copyFromNext(SeekerState that) {
      super.copyFromNext(that);
      FastDiffSeekerState other = (FastDiffSeekerState) that;
      System.arraycopy(other.prevTimestampAndType, 0, prevTimestampAndType, 0,
        KeyValue.TIMESTAMP_TYPE_SIZE);
      rowLengthWithSize = other.rowLengthWithSize;
      familyLengthWithSize = other.familyLengthWithSize;
    }
Copies the first key/value from the given stream, and initializes decompression state based
on it. Assumes that we have already read key and value lengths. Does not set
{@link #qualifierLength} (not used by decompression) or {@link #prevOffset} (set by the calle
afterwards).
hbase-common/src/main/java/org/apache/hadoop/hbase/io/encoding/FastDiffDeltaEncoder.java