message: remove dead indexing code
diff: @@ -198,24 +198,16 @@ impl SegmentWriter {
  }
  FieldType::Str(_) => {
  let mut token_streams: Vec<BoxTokenStream> = vec![];
  - let mut offsets = vec![];
  - let mut total_offset = 0;
  for value in values {
  match value {
  Value::PreTokStr(tok_str) => {
  - offsets.push(total_offset);
  - if let Some(last_token) = tok_str.tokens.last() {
  - total_offset += last_token.offset_to;
  - }
  token_streams
  .push(PreTokenizedStream::from(tok_str.clone()).into());
  }
  Value::Str(ref text) => {
  let text_analyzer =
  &self.per_field_text_analyzers[field.field_id() as usize];
  - offsets.push(total_offset);
  - total_offset += text.len();
  token_streams.push(text_analyzer.token_stream(text));
  }
  _ => (),
  