NOTE: One side-effect of this design change is that all offline-mode code can
  be isolated to maven-core, maven-plugin-descriptor, and [possibly]
  maven-artifact. Usage of maven-wagon will be determined by an offline-aware
  manager.

* Assumptions: What is Offline?

  For the purposes of determining the areas sensitive to offline status,
  it is definitely useful to define what the offline state really means.