Adds an allow or block rule to the mailbox. Rules match the message's envelope sender; domain entries also match subdomains. Block rules always win — over allow rules and over the reply admission on allowlist mailboxes. An entry can be allow or block, never both: to flip it, delete the rule and re-create it. A mailbox holds up to 200 rules. What the rule does when it matches. Block rules always win. To flip an entry's action, delete the existing rule and re-create it. Possible values: `allow`, `block` The sender address (`alice@example.com`) or domain (`example.com`) to match. Domains also match their subdomains. Stored lowercase. Your own note about why the rule exists. Receive rule ID. The mailbox the rule applies to. What the rule does when it matches. Block rules always win — over allow rules and over the reply admission on allowlist mailboxes. Possible values: `allow`, `block` The sender address or domain the rule matches. Domains also match their subdomains. Whether the entry is a full address or a domain. Possible values: `address`, `domain` Your own note about why the rule exists. Null when unset. When the rule was created.