code: public Observable<CredentialInner> createOrUpdateAsync(String resourceGroupName, String automationAccountName, String credentialName, CredentialCreateOrUpdateParameters parameters) {
          return createOrUpdateWithServiceResponseAsync(resourceGroupName, automationAccountName, credentialName, parameters).map(new Func1<ServiceResponse<CredentialInner>, CredentialInner>() {
              @Override
              public CredentialInner call(ServiceResponse<CredentialInner> response) {
                  return response.body();
              }
          });
      }
docs: Create a credential.
  
  @param resourceGroupName Name of an Azure Resource group.
  @param automationAccountName The name of the automation account.
  @param credentialName The parameters supplied to the create or update credential operation.
  @param parameters The parameters supplied to the create or update credential operation.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the CredentialInner object