private static Map<String, String> emailToId = Map.of(
            "email@mydomain", "123456789deadbeef000000000",
    );


public static EmailRoutingRule createRule(final String from, final String to)
{
    final var name = from + ":rule";
    final var rule = EmailRoutingRuleArgs.builder()
            .actions(
                    EmailRoutingRuleActionArgs.builder()
                            .type("forward")
                            .values(to)
                            .build()
            )
            .enabled(true)
            .matchers(
                    EmailRoutingRuleMatcherArgs.builder()
                            .field("to")
                            .type("literal")
                            .value(from)
                            .build()
            )
            .name(name)
            .zoneId(ZONE_ID_MY_DOMAIN)
            .build();

    final var optionsBuilder = CustomResourceOptions.builder();
    Optional.ofNullable(emailToId.get(from)).ifPresent(optionsBuilder::importId);

    return  new EmailRoutingRule
    (
            name,
            rule,
            optionsBuilder.build()
            );
}

cloudflare:index:EmailRoutingRule (email@mydomain:rule):
    error: Preview failed: refreshing urn:pulumi:dev::cloudflare::cloudflare:index/emailRoutingRule:EmailRoutingRule::email@mydomain:rule: 1 error occurred:
        * error reading email routing rule "123456789deadbeef000000000": required missing zone ID