anchor.diff:   */
   class Builder {
     final int initialSize;
  +
  +  /**
  +   * The list of field tails, reused by [_VTable] instances.
  +   */
  +  final Int32List _reusedFieldTails = Int32List(1024);
  +
  +  /**
  +   * The list of field offsets, reused by [_VTable] instances.
  +   */
  +  final Int32List _reusedFieldOffsets = Int32List(1024);
   
     /**
      * The list of existing VTable(s).
  
positive.code:     buf.setUint16(bufOffset, tableSize, Endian.little);
      bufOffset += 2;
      // Field offsets.
      for (int fieldOffset in fieldOffsets) {
        buf.setUint16(bufOffset, fieldOffset, Endian.little);
        bufOffset += 2;
      }
    }
  }
  
negative.code:  * Class that describes the structure of a table.
   */
  class _VTable {
    final Int32List _reusedFieldTails;
    final Int32List _reusedFieldOffsets;
  
    /**
     * The number of fields in [_reusedFieldTails].
     */
    int _fieldCount = 0;
  
    /**
     * The private copy of [_reusedFieldOffsets], which is made only when we
     * find that this table is unique.
     */
    Int32List _fieldOffsets;
  
    /**
     * The size of the table that uses this VTable.
  