Identifier of the user or chat that completed the task; may be null if the task isn't completed yet.
Point in time (Unix timestamp) when the task was completed; 0 if the task isn't completed.
Unique identifier of the task.
Text of the task; may contain only Bold, Italic, Underline, Strikethrough, Spoiler, CustomEmoji, DateTime and automatically found entities.
Describes a task in a checklist.