MultiStep creates a new MultiStep implementation.

NewLoop creates a new Loop based progress implementation.

Set defines the default progress client implementation.

BaseProgress is the common implementation between MultiStep and Loop progress.

Loop defines the specific data for Loop progress implementation.

Client is the interface a frontend must implement in order to be notified about the install progress.

Progress is the internal interface for the progress subsystem, currently we have two different implementations a MultiStep and a Loop based one.