我想將 Observable 對象轉換為 json 對象ObjectMapper mapper = new ObjectMapper();    Observable<String> response = accountSearchService.searchAccount(paramMap, "", 0, 1);    mapper.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);    AccountSearchResult resultDto = mapper.convertValue(response.subscribe().toString(), AccountSearchResult.class);這就是我想要做的，但得到 OnErrorNotImplementedException。請有人幫助我。