public GrpcServiceBuilder enableHealthCheckService(boolean enableHealthCheckService) {
        if (grpcHealthCheckService != null && enableHealthCheckService) {
            throw new IllegalStateException("gRPC health check service is set already.");
        }
        this.enableHealthCheckService = enableHealthCheckService;
        return this;
    }
Sets the default {@link GrpcHealthCheckService} to this {@link GrpcServiceBuilder}.
The gRPC health check service manages only the health checker that determines
the healthiness of the {@link Server}.

@see
<a href="https://github.com/grpc/grpc/blob/master/doc/health-checking.md">GRPC Health Checking Protocol</a>
grpc/src/main/java/com/linecorp/armeria/server/grpc/GrpcServiceBuilder.java