code: public Observable<CertificateInner> createOrUpdateAsync(String resourceGroupName, String name, CertificateInner certificateEnvelope) {
          return createOrUpdateWithServiceResponseAsync(resourceGroupName, name, certificateEnvelope).map(new Func1<ServiceResponse<CertificateInner>, CertificateInner>() {
              @Override
              public CertificateInner call(ServiceResponse<CertificateInner> response) {
                  return response.body();
              }
          });
      }
docs: Create or update a certificate.
  Create or update a certificate.
  
  @param resourceGroupName Name of the resource group to which the resource belongs.
  @param name Name of the certificate.
  @param certificateEnvelope Details of certificate, if it exists already.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the CertificateInner object