code: public Observable<ServiceResponse<FileStorageInfoInner>> readWithServiceResponseAsync(String groupName, String serviceName, String projectName, String fileName) {
          if (this.client.subscriptionId() == null) {
              throw new IllegalArgumentException("Parameter this.client.subscriptionId() is required and cannot be null.");
          }
          if (groupName == null) {
              throw new IllegalArgumentException("Parameter groupName is required and cannot be null.");
          }
          if (serviceName == null) {
              throw new IllegalArgumentException("Parameter serviceName is required and cannot be null.");
          }
          if (projectName == null) {
              throw new IllegalArgumentException("Parameter projectName is required and cannot be null.");
          }
          if (fileName == null) {
              throw new IllegalArgumentException("Parameter fileName is required and cannot be null.");
          }
          if (this.client.apiVersion() == null) {
              throw new IllegalArgumentException("Parameter this.client.apiVersion() is required and cannot be null.");
          }
          return service.read(this.client.subscriptionId(), groupName, serviceName, projectName, fileName, this.client.apiVersion(), this.client.acceptLanguage(), this.client.userAgent())
              .flatMap(new Func1<Response<ResponseBody>, Observable<ServiceResponse<FileStorageInfoInner>>>() {
                  @Override
                  public Observable<ServiceResponse<FileStorageInfoInner>> call(Response<ResponseBody> response) {
                      try {
                          ServiceResponse<FileStorageInfoInner> clientResponse = readDelegate(response);
                          return Observable.just(clientResponse);
                      } catch (Throwable t) {
                          return Observable.error(t);
                      }
                  }
              });
      }
docs: Request storage information for downloading the file content.
  This method is used for requesting storage information using which contents of the file can be downloaded.
  
  @param groupName Name of the resource group
  @param serviceName Name of the service
  @param projectName Name of the project
  @param fileName Name of the File
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the FileStorageInfoInner object