docs: @BetaApi
    public final Operation insertTargetVpnGateway(
        String region, TargetVpnGateway targetVpnGatewayResource) {
  
      InsertTargetVpnGatewayHttpRequest request =
          InsertTargetVpnGatewayHttpRequest.newBuilder()
              .setRegion(region)
              .setTargetVpnGatewayResource(targetVpnGatewayResource)
              .build();
      return insertTargetVpnGateway(request);
    }