Optionalcompleted_Chat that completed the task; omitted if the task wasn't completed by a chat.
Optionalcompleted_User that completed the task; omitted if the task wasn't completed by a user.
Optionalcompletion_Point in time (Unix timestamp) when the task was completed; 0 if the task wasn't completed.
Unique identifier of the task.
Text of the task.
Optionaltext_Special entities that appear in the task text.
Describes a task in a checklist.
See
Telegram Bot API: ChecklistTask