docs: @BetaApi
    public final Operation deleteTargetVpnGateway(String targetVpnGateway) {
  
      DeleteTargetVpnGatewayHttpRequest request =
          DeleteTargetVpnGatewayHttpRequest.newBuilder()
              .setTargetVpnGateway(targetVpnGateway)
              .build();
      return deleteTargetVpnGateway(request);
    }