questions re the ChainingMetadataProvider type

[Rod Widdowson]

> Yes, that is needed, but that won't fix the basic problem. The
> ChainingMetadataProvider type is not like the other metadata providers
> yet it inherits from the same abstract base type
> (MetadataProviderType). It really is its own animal.

Well that could be fixed, but I don't see that this has anything to do with the documentation.  The documentation should describe
what works and what doesn't and how.    The schema is a nicety to help some development and some people debug their configuration.
The structure of the code and the structure of the schema need not have any impact on the documentation.  

You specify an invalid configuration?  It's going to barf and if it doesn't it should.  If it doesn’t either the documentation is
wrong or the code is wrong, but the schema is irrelevant at that level.  UNLESS  you want to consider the schema as partial
documentation and for that reason only we ot behoves us to keep it as up to date as possible.