Returns a single conversation. Fetch the messages in the conversation with `GET /v1/email/threads/{thread_id}/messages`. A thread whose retention period has ended returns `410 Gone`. Thread ID. Mailbox this conversation belongs to. Channel this conversation lives on. Always `email`. Contact linked to this conversation, or null when none is linked. Subject of the conversation, taken from its first message. Null when that message had no subject. Addresses that appear on the retained messages in this conversation, including the mailbox's own address. Number of retained messages in this conversation, both directions. Number of retained received messages that are still unread. Spam and blocked mail is not counted. When the most recent retained message in this conversation was received or sent. Direction of the most recent message — `inbound` for a received message, `outbound` for a sent one. Possible values: `inbound`, `outbound` Labels on this conversation. Exactly one system placement label is always present — `inbox`, `archive` (filed away, done for now), `spam` (the opening message failed sender authentication), or `blocked` (rejected by the mailbox's receive policy or rules) — set by the message that started the conversation. Move a conversation by updating its labels: add `spam` to file it as spam, add `archive` to clean it out of the inbox, and add `inbox` — or remove `spam`, `blocked`, or `archive` — to bring it back. An archived conversation returns to the inbox by itself when a new message arrives. Custom labels share the same list; a conversation carries at most 20. When the thread was created. When the thread last changed. Matched search fragments, keyed by the field that matched. Returned only by thread search; omitted when listing threads. Matched fragments from the conversation's subject. Matched fragments from a message's body text.