Reads the commands packed into a frame options field, or a payload sent on port zero.

The same identifier means a different command in each direction, so the direction decides what is read and there is no default.

A command does not carry its own length, so one this build does not know cannot be stepped over. Reading stops there, and what came before it is returned.

Arguments

• direction - which way the frame carrying them travels.
• bytes - the options field, or the payload.

Returns

The commands that were readable, in order.