This must wrap the datatype used to set the io field of any Module. i.e. All concrete modules must have defined io in this form: [lazy] val io[: io type] = IO(...[: io type])
Items in [] are optional.
The granted iodef must be a chisel type and not be bound to hardware.
Also registers a Data as a port, also performing bindings. Cannot be called once ports are requested (so that all calls to ports will return the same information).