Container Data

Packet ID	Direction	Mojang Name	MCP Name
`0x69`	Clientbound	`ContainerSetDataPacket`	`Packet105UpdateProgressbar`

This is sent by the server to update the furnace GUI's progress bars.

Clientbound

Field	Type	Description
Window ID	Byte	The incremental ID of the window. Ranges from 0 to 99
Type	Short (Type)	The type of data.
Value	Short	The value of the data.

ID	Name	Range	Description
`0`	Smelting Progress	`0` to `200`	The progress of the current item being smelted.
`1`	Fuel Remaining	`0` to (fuel duration)	A higher value means more fuel remaining.
`2`	Fuel Duration	`0` to `20000`	The burning time of the current fuel item (defaults to `200` if not sent)

See the smelting page for more info on what counts as valid fuel and for how long said fuel burns.