code: @BetaApi
    public final ListTargetVpnGatewaysPagedResponse listTargetVpnGateways(ProjectRegionName region) {
      ListTargetVpnGatewaysHttpRequest request =
          ListTargetVpnGatewaysHttpRequest.newBuilder()
              .setRegion(region == null ? null : region.toString())
              .build();
      return listTargetVpnGateways(request);
    }
docs: Retrieves a list of target VPN gateways available to the specified project and region.
  
  <p>Sample code:
  
  <pre><code>
  try (TargetVpnGatewayClient targetVpnGatewayClient = TargetVpnGatewayClient.create()) {
  ProjectRegionName region = ProjectRegionName.of("[PROJECT]", "[REGION]");
  for (TargetVpnGateway element : targetVpnGatewayClient.listTargetVpnGateways(region).iterateAll()) {
  // doThingsWith(element);
  }
  }
  </code></pre>
  
  @param region Name of the region for this request.
  @throws com.google.api.gax.rpc.ApiException if the remote call fails