public GrpcHealthCheckServiceBuilder checkers(ListenableHealthChecker... serverHealthCheckers) {
        return checkers(ImmutableSet.copyOf(requireNonNull(serverHealthCheckers, "healthCheckers")));
    }
Adds the specified {@link ListenableHealthChecker}s that determine the healthiness of the {@link Server}.
grpc/src/main/java/com/linecorp/armeria/server/grpc/GrpcHealthCheckServiceBuilder.java