docs: public static void flush(Flushable flushable, boolean swallowIOException) throws IOException {
      try {
        flushable.flush();
      } catch (IOException e) {
        if (swallowIOException) {
          logger.log(Level.WARNING, "IOException thrown while flushing Flushable.", e);
        } else {
          throw e;
        }
      }
    }