* X-GM-LABELS: string value which allows you to search for specific messages that have the given label applied
* fetch() will automatically retrieve the thread id, unique message id, and labels (named 'x-gm-thrid', 'x-gm-msgid', 'x-gm-labels' respectively) and will be stored on the _ImapMessage_ object itself
* fetch() will automatically retrieve the thread id, unique message id, and labels (named 'x-gm-thrid', 'x-gm-msgid', 'x-gm-labels' respectively) and they will be stored on the _ImapMessage_ object itself