public SELF clientFactory(ClientFactory clientFactory) {
        clientOptionsBuilder.factory(requireNonNull(clientFactory, "clientFactory"));
        return self();
    }
Sets the {@link ClientFactory} to use when making health check requests. This should generally be the
same as the {@link ClientFactory} used when creating a {@link Client} stub using the
{@link EndpointGroup}.
core/src/main/java/com/linecorp/armeria/client/endpoint/healthcheck/AbstractHealthCheckedEndpointGroupBuilder.java