GMount and GVolume

Question

I am new to GIO and I am totally confused between GMount and GVolume. The GIO reference says that GMount is a "mounted" filesystem that you can access while GVolume represents user-visible objects that can be mounted. I have a few questions about these two types.

1. Is a mounted GVolume object equivalent to a GMount object?
2. A mounted GVolume object is always associated with a GMount object. What is the relationship between them?
3. A GMount object may or may not be associated with a GVolume object. When is it not associated with the latter?

Answer 1

In short:

1. No.
2. Yes, 1-1 relationship by the way.
3. Virtual devices such as fpt:// etc. have only a Gmount without a GVolume.