Defines a min user that was seen in a certain message of a certain chat.
inputUserFromMessage#1da448e2 peer:InputPeer msg_id:int user_id:long = InputUser;
|peer||InputPeer||The chat where the user was seen|
|msg_id||int||The message ID|
|user_id||long||The identifier of the user that was seen|
In some situations user and channel constructors have reduced set of fields present (although id is always there) and min flag set.