The user presence is being updated for

The user object within this event can be partial, the only field which must be sent is the id field, everything else is optional.

See https://discord.com/developers/docs/resources/user#user-object

ID of the guild

Either "idle", "dnd", "online", or "offline"

User's current activities

See https://discord.com/developers/docs/topics/gateway#activity-object

User's platform-dependent status

See https://discord.com/developers/docs/topics/gateway#client-status-object