When you send a fax using the API, the response will contain the `messageId`. You can also look this up in the `message-store` or `call-log` APIs.
Then you can use the `messageId` to associate the message in the `message-store` and `call-log` endpoints. The message store entry includes information on the canonical message while the call log record includes information on a specific transmission attempt. The call log entry has a `message` property with both `message.id` and `message.url` properties for cross referencing.