code: public RpcInternalContext setAttachments(Map<String, Object> attachments) {
          if (attachments != null && attachments.size() > 0) {
              for (Map.Entry<String, Object> entry : attachments.entrySet()) {
                  setAttachment(entry.getKey(), entry.getValue());
              }
          }
          return this;
      }
docs: key不能以点和下划线开头
  
  @param attachments the attachments
  @return context attachments