code: public Observable<ServiceResponse<ImageRegionProposal>> getImageRegionProposalsWithServiceResponseAsync(UUID projectId, UUID imageId) {
          if (projectId == null) {
              throw new IllegalArgumentException("Parameter projectId is required and cannot be null.");
          }
          if (imageId == null) {
              throw new IllegalArgumentException("Parameter imageId is required and cannot be null.");
          }
          if (this.client.apiKey() == null) {
              throw new IllegalArgumentException("Parameter this.client.apiKey() is required and cannot be null.");
          }
          return service.getImageRegionProposals(projectId, imageId, this.client.apiKey(), this.client.acceptLanguage(), this.client.userAgent())
              .flatMap(new Func1<Response<ResponseBody>, Observable<ServiceResponse<ImageRegionProposal>>>() {
                  @Override
                  public Observable<ServiceResponse<ImageRegionProposal>> call(Response<ResponseBody> response) {
                      try {
                          ServiceResponse<ImageRegionProposal> clientResponse = getImageRegionProposalsDelegate(response);
                          return Observable.just(clientResponse);
                      } catch (Throwable t) {
                          return Observable.error(t);
                      }
                  }
              });
      }
docs: Get region proposals for an image. Returns empty array if no proposals are found.
  This API will get region proposals for an image along with confidences for the region. It returns an empty array if no proposals are found.
  
  @param projectId The project id
  @param imageId The image id
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the ImageRegionProposal object