code: public int writeValue( DataOutputStream out, boolean reset )
                            throws IOException {
       if ( size <= 0 ) {
         return 0;
       }
  
       if ( size == 4 ) {
         out.writeInt( (int) summer.getValue() );
       } else {
         throw new IOException( "Unknown Checksum " + type );
       }
       
       if ( reset ) {
         reset();
       }
       
       return size;
     }
docs: Writes the current checksum to the stream.
  If <i>reset</i> is true, then resets the checksum.
  @return number of bytes written. Will be equal to getChecksumSize();