code: public VpnSiteInner createOrUpdate(String resourceGroupName, String vpnSiteName, VpnSiteInner vpnSiteParameters) {
          return createOrUpdateWithServiceResponseAsync(resourceGroupName, vpnSiteName, vpnSiteParameters).toBlocking().last().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
  @throws ErrorException thrown if the request is rejected by server
  @throws RuntimeException all other wrapped checked exceptions if the request fails to be sent
  @return the VpnSiteInner object if successful.