Draft
constructor(inboxId: String, draftId: String, labels: List<String> = emptyList(), timestamp: Instant, from: String? = null, to: List<String> = emptyList(), cc: List<String> = emptyList(), bcc: List<String> = emptyList(), subject: String? = null, preview: String? = null, text: String? = null, html: String? = null, attachments: List<Attachment> = emptyList(), updatedAt: Instant, createdAt: Instant)