docs: @SuppressWarnings("unused")
      final void handleHeaderValue(ByteBuffer buffer, ParseState state, HttpServerExchange builder) throws BadRequestException {
          HttpString headerName = state.nextHeader;
          StringBuilder stringBuilder = state.stringBuilder;
          CacheMap<HttpString, String> headerValuesCache = state.headerValuesCache;
          if (headerName != null && stringBuilder.length() == 0 && headerValuesCache != null) {
              String existing = headerValuesCache.get(headerName);
              if (existing != null) {
                  if (handleCachedHeader(existing, buffer, state, builder)) {
                      return;
                  }
              }
          }
  
          handleHeaderValueCacheMiss(buffer, state, builder, headerName, headerValuesCache, stringBuilder);
      }