code: public Observable<ServiceResponse<VpnSiteInner>> createOrUpdateWithServiceResponseAsync(String resourceGroupName, String vpnSiteName, VpnSiteInner vpnSiteParameters) {
          if (this.client.subscriptionId() == null) {
              throw new IllegalArgumentException("Parameter this.client.subscriptionId() is required and cannot be null.");
          }
          if (resourceGroupName == null) {
              throw new IllegalArgumentException("Parameter resourceGroupName is required and cannot be null.");
          }
          if (vpnSiteName == null) {
              throw new IllegalArgumentException("Parameter vpnSiteName is required and cannot be null.");
          }
          if (vpnSiteParameters == null) {
              throw new IllegalArgumentException("Parameter vpnSiteParameters is required and cannot be null.");
          }
          Validator.validate(vpnSiteParameters);
          final String apiVersion = "2018-06-01";
          Observable<Response<ResponseBody>> observable = service.createOrUpdate(this.client.subscriptionId(), resourceGroupName, vpnSiteName, apiVersion, vpnSiteParameters, this.client.acceptLanguage(), this.client.userAgent());
          return client.getAzureClient().getPutOrPatchResultAsync(observable, new TypeToken<VpnSiteInner>() { }.getType());
      }
docs: Creates a VpnSite resource if it doesn't exist else updates the existing VpnSite.
  
  @param resourceGroupName The resource group name of the VpnSite.
  @param vpnSiteName The name of the VpnSite being created or updated.
  @param vpnSiteParameters Parameters supplied to create or update VpnSite.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable for the request