code: public Observable<CertificateBundle> getCertificateAsync(String vaultBaseUrl, String certificateName, String certificateVersion) {
          return getCertificateWithServiceResponseAsync(vaultBaseUrl, certificateName, certificateVersion).map(new Func1<ServiceResponse<CertificateBundle>, CertificateBundle>() {
              @Override
              public CertificateBundle call(ServiceResponse<CertificateBundle> response) {
                  return response.body();
              }
          });
      }
docs: Gets information about a certificate.
  Gets information about a specific certificate. This operation requires the certificates/get permission.
  
  @param vaultBaseUrl The vault name, for example https://myvault.vault.azure.net.
  @param certificateName The name of the certificate in the given vault.
  @param certificateVersion The version of the certificate.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the CertificateBundle object