code: public static List<WriteFuture> broadcast(Object message, IoSession... sessions) {
          if (sessions == null) {
              sessions = EMPTY_SESSIONS;
          }
          
          List<WriteFuture> answer = new ArrayList<>(sessions.length);
          if (message instanceof IoBuffer) {
              for (IoSession s: sessions) {
                  answer.add(s.write(((IoBuffer) message).duplicate()));
              }
          } else {
              for (IoSession s: sessions) {
                  answer.add(s.write(message));
              }
          }
          return answer;
      }
docs: Writes the specified {@code message} to the specified {@code sessions}.
  If the specified {@code message} is an {@link IoBuffer}, the buffer is
  automatically duplicated using {@link IoBuffer#duplicate()}.