code: public Observable<String> cloneAsync(UUID appId, String versionId, CloneOptionalParameter cloneOptionalParameter) {
          return cloneWithServiceResponseAsync(appId, versionId, cloneOptionalParameter).map(new Func1<ServiceResponse<String>, String>() {
              @Override
              public String call(ServiceResponse<String> response) {
                  return response.body();
              }
          });
      }
docs: Creates a new version using the current snapshot of the selected application version.
  
  @param appId The application ID.
  @param versionId The version ID.
  @param cloneOptionalParameter the object representing the optional parameters to be set before calling this API
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the String object