- There are many situations in which a message contains a payload that contains content that adds additional information to the context of a previous message. Examples of this might be a user sending a rection (e.g. a thumbs-up emoji) to another user's message, or a server adding information on a link previously posted to a chat room, a user updating/editing the content of a message they've previously sent. This specification provides a generic wrapper to fasten such new payloads to the message to which they apply. + There are many situations in which a message contains a payload that contains content that adds additional information to the context of a previous message. Examples of this might be a user sending a reaction (e.g. a thumbs-up emoji) to another user's message, or a server adding information on a link previously posted to a chat room, a user updating/editing the content of a message they've previously sent. This specification provides a generic wrapper to fasten such new payloads to the message to which they apply.