code: public ServiceFuture<CertificateWithNonceDescriptionInner> generateVerificationCodeAsync(String resourceGroupName, String resourceName, String certificateName, String ifMatch, final ServiceCallback<CertificateWithNonceDescriptionInner> serviceCallback) {
          return ServiceFuture.fromResponse(generateVerificationCodeWithServiceResponseAsync(resourceGroupName, resourceName, certificateName, ifMatch), serviceCallback);
      }
docs: Generate verification code for proof of possession flow.
  Generates verification code for proof of possession flow. The verification code will be used to generate a leaf certificate.
  
  @param resourceGroupName The name of the resource group that contains the IoT hub.
  @param resourceName The name of the IoT hub.
  @param certificateName The name of the certificate
  @param ifMatch ETag of the Certificate.
  @param serviceCallback the async ServiceCallback to handle successful and failed responses.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceFuture} object