public GrpcHealthCheckServiceBuilder checkers(
            Iterable<? extends ListenableHealthChecker> serverHealthCheckers) {
        this.serverHealthCheckers.addAll(requireNonNull(serverHealthCheckers, "healthCheckers"));
        return this;
    }
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