code: public static Filter toTimestampRangeFilter(long bigtableStartTimestamp,
        long bigtableEndTimestamp) {
      return FILTERS.timestamp().range().of(bigtableStartTimestamp, bigtableEndTimestamp);
    }
docs: Converts a [startMicros, endNons) timestamps to a Cloud Bigtable [startMicros, endMicros)
  filter.
  
  @param bigtableStartTimestamp a long value.
  @param bigtableEndTimestamp a long value.
  @return a {@link Filter} object.