code: public static void readLongSequence(DataInput in, long[] seqnos, int index) throws IOException {
          byte len=in.readByte();
          if(len == 0) {
              seqnos[index]=seqnos[index+1]=0;
              return;
          }
          byte len1=firstNibble(len), len2=secondNibble(len);
          seqnos[index]=makeLong(in, len1);
          seqnos[index+1]=makeLong(in, len2) + seqnos[index];
      }
docs: Reads 2 compressed longs into an array of 2 longs.
  <p/>
  Once variable-length encoding has been implemented, this method will probably get dropped as we can simply
  read the 2 longs individually.
  @param in the input stream to read from
  @param seqnos the array to read the seqnos into, needs to have a length of 2
  @param index the index of the first element to be written; the seqnos are written to seqnos[index] and seqnos[index+1]