docs: @BetaApi
    public final Operation insertTargetInstance(
        ProjectZoneName zone, TargetInstance targetInstanceResource) {
  
      InsertTargetInstanceHttpRequest request =
          InsertTargetInstanceHttpRequest.newBuilder()
              .setZone(zone == null ? null : zone.toString())
              .setTargetInstanceResource(targetInstanceResource)
              .build();
      return insertTargetInstance(request);
    }