code: public Observable<VersionInfo> getAsync(UUID appId, String versionId) {
          return getWithServiceResponseAsync(appId, versionId).map(new Func1<ServiceResponse<VersionInfo>, VersionInfo>() {
              @Override
              public VersionInfo call(ServiceResponse<VersionInfo> response) {
                  return response.body();
              }
          });
      }
docs: Gets the version info.
  
  @param appId The application ID.
  @param versionId The version ID.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the VersionInfo object