Returns the lifecycle event timeline for a message, in chronological order. Message ID. Filter by event type (e.g. `sms.delivered`, `sms.failed`). Timeline events for this SMS message, in chronological order. The timeline is bounded and returned in full — this list is not paginated. Event ID. Lifecycle event type. `sms.accepted` — Bird accepted the request. `sms.sent` — handed to the carrier. `sms.delivered` — delivery confirmed. `sms.undelivered` — non-permanent non-delivery. `sms.failed` — terminal permanent failure. `sms.rejected` — refused before reaching the carrier. `sms.expired` — the validity period elapsed. Open enum — new event types may be added over time, so treat any unrecognized value as a future event rather than an error. Possible values (may grow over time): `sms.accepted`, `sms.sent`, `sms.delivered`, `sms.undelivered`, `sms.failed`, `sms.rejected`, `sms.expired` When this event occurred. Carrier that handled the message. Present on `sms.sent` and `sms.delivered` once identified, absent otherwise. Mobile country code and mobile network code of the carrier. Present on `sms.sent` and `sms.delivered` once identified, absent otherwise. Failure detail. Present only on `sms.failed`, `sms.undelivered`, `sms.rejected`, and `sms.expired` events. Bird-stable failure reason. Open enum: Bird adds reasons as the carrier platform's own buckets are covered, so treat an unrecognized value as a future reason rather than an error. `invalid_destination`: the number is not assigned, ported out, or malformed. `unreachable`: handset off or out of coverage. `blocked_by_carrier`: the carrier filtered the message. `blocked_by_recipient`: the recipient device blocked the sender. `landline_unreachable`: the destination is a landline that does not accept SMS. `content_rejected`: the carrier rejected the content. `sender_unregistered`: the sender is not registered for the destination. `recipient_opted_out`: the recipient is on a suppression list. `provider_unavailable`: an upstream failure after retries. `insufficient_balance`: the workspace wallet had insufficient balance to send the message. `unknown`: an unmapped failure. Possible values (may grow over time): `invalid_destination`, `unreachable`, `blocked_by_carrier`, `blocked_by_recipient`, `landline_unreachable`, `content_rejected`, `sender_unregistered`, `recipient_opted_out`, `provider_unavailable`, `insufficient_balance`, `unknown` Human-readable explanation of the failure. Raw provider-supplied error code, finer-grained than the `code` that normalizes it. Not a Bird-defined value, so quote it to support when asking why a message failed. Null when the provider sent none, including any failure decided before one was reached. When the failure occurred.