docs: public boolean masterStarted() {
          if (objectMapper == null)
              objectMapper = new ObjectMapper();
  
          try {
              String type = objectMapper.readValue(
                              Unirest.get(String.format("http://%s:%d/opType", masterStatusHost, masterStatusPort)).asJson()
                                              .getBody().toString(),
                              ServerTypeJson.class).getType();
              if (!type.equals("master"))
                  throw new IllegalStateException("Wrong opType " + type);
              Unirest.get(String.format("http://%s:%d/started", masterStatusHost, masterStatusPort)).asJson().getBody();
              return objectMapper.readValue(
                              Unirest.get(String.format("http://%s:%d/started", masterStatusHost, masterStatusPort))
                                              .asJson().getBody().toString(),
                              MasterStatus.class).started();
          } catch (Exception e) {
              e.printStackTrace();
          }
          return false;
      }