Question

Since Attributes are really just Metadata attached to assemblies, does that mean that Attribute Objects are only created on request (such as when you call GetCustomAttributes)?

Or are they created on creation of the object?

Or, a combination of the first 2, created when the object is created due to attribute scanning by the CLR?

Answer 1

From CLR via C#, third edition:

If you want to construct an attribute object, you must call either GetCustomAttributes or
GetCustomAttribute. Every time one of these methods is called, it constructs new instances
of the specified attribute type and sets each of the instance’s fields and properties based on the values specified in the source code. These methods return references to fully constructed instances of the applied attribute classes.

So yes, they are only created on request.