code: public Observable<CertificateBundle> recoverDeletedCertificateAsync(String vaultBaseUrl, String certificateName) {
          return recoverDeletedCertificateWithServiceResponseAsync(vaultBaseUrl, certificateName).map(new Func1<ServiceResponse<CertificateBundle>, CertificateBundle>() {
              @Override
              public CertificateBundle call(ServiceResponse<CertificateBundle> response) {
                  return response.body();
              }
          });
      }
docs: Recovers the deleted certificate back to its current version under /certificates.
  The RecoverDeletedCertificate operation performs the reversal of the Delete operation. The operation is applicable in vaults enabled for soft-delete, and must be issued during the retention interval (available in the deleted certificate's attributes). This operation requires the certificates/recover permission.
  
  @param vaultBaseUrl The vault name, for example https://myvault.vault.azure.net.
  @param certificateName The name of the deleted certificate
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the CertificateBundle object