| Name | Type | Description | Notes |
|---|---|---|---|
| to_user_id | Option<i32> | User ID of the recipient | [optional] |
| thread_id | Option<i32> | Identifier for the thread. Should be blank for new threads, but when replying to an existing message, it should be set to the thread_id of the message being replied to. | [optional] |
| subject | Option<String> | Subject of the message | [optional] |
| body | Option<String> | Body of the message | [optional] |