public override FieldsProducer FieldsProducer(SegmentReadState state)
        {
            PostingsReaderBase postingsReader = new SepPostingsReader(state.Directory,
                                                                      state.FieldInfos,
                                                                      state.SegmentInfo,
                                                                      state.Context,
                                                                      new MockIntFactory(baseBlockSize), state.SegmentSuffix);

            TermsIndexReaderBase indexReader;
            bool success = false;
            try
            {
                indexReader = new FixedGapTermsIndexReader(state.Directory,
                                                                 state.FieldInfos,
                                                                 state.SegmentInfo.Name,
                                                                 state.TermsIndexDivisor,
                                                                 BytesRef.UTF8SortedAsUnicodeComparer,
                                                                 state.SegmentSuffix, state.Context);
                success = true;
            }
            finally
            {
                if (!success)
                {
                    postingsReader.Dispose();
                }
            }

            success = false;
            try
            {
                FieldsProducer ret = new BlockTermsReader(indexReader,
                                                          state.Directory,
                                                          state.FieldInfos,
                                                          state.SegmentInfo,
                                                          postingsReader,
                                                          state.Context,
                                                          state.SegmentSuffix);
                success = true;
                return ret;
            }
            finally
            {
                if (!success)
                {
                    try
                    {
                        postingsReader.Dispose();
                    }
                    finally
                    {
                        indexReader.Dispose();
                    }
                }
            }
        }