code: public Observable<VpnSiteInner> beginCreateOrUpdateAsync(String resourceGroupName, String vpnSiteName, VpnSiteInner vpnSiteParameters) {
          return beginCreateOrUpdateWithServiceResponseAsync(resourceGroupName, vpnSiteName, vpnSiteParameters).map(new Func1<ServiceResponse<VpnSiteInner>, VpnSiteInner>() {
              @Override
              public VpnSiteInner call(ServiceResponse<VpnSiteInner> response) {
                  return response.body();
              }
          });
      }
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 to the VpnSiteInner object