docs: void roll() {
          if (m_logger.isTraceEnabled()) {
              m_logger.trace("Rolling batch.");
          }
          Map<RollingDecoder,HttpExportDecoder> decoderMap;
          synchronized(m_tableDecoders) {
              decoderMap = ImmutableMap.copyOf(m_tableDecoders);
          }
          m_logger.info("Rolling " + decoderMap.size() + " number of data sources.");
  
          for (Map.Entry<RollingDecoder,HttpExportDecoder> entry : decoderMap.entrySet()) {
              entry.getValue().m_exportPath = null;
          }
      }