Delay DbCommandInterceptor.CommandCreated until DbCommand properties are initialized

[divega]

I was hoping I could now log the CommandText from this method without having to override Execut* methods, but the DbCommand exposed as the result of CommandCreated is empty.

We discussed with @ajcvickers that having the properties populated could be more useful, but it is likely we don't have time to change this for 3.0 RTM, in which case we can add "CommandInitialized" method later.

[ajcvickers]

Compare to #15988

[simeyla]

@ajcvickers I was excited to see the following in the EF Core 5 New Features:

"In addition, it is now possible to call ToQueryString on any LINQ query, retrieving the SQL that the query would execute"

I've added my own DBInterceptor to add NOEXPAND hints and it works great.

However if I run ToQueryString() during debugging I won't see my hint in the SQL since I am relying on ReaderExecutingAsync and ReaderExecuting to perform the modification of the underlying command string.

It seems a shame that CommandCreating and CommandCreated seem to be intended only for fully comprehensive interception, but not for the simpler cases. It would also be nice not to have to consider overloading both ReaderExecutingAsync and ReaderExecuting.

I know it's sort of an edge case and easy to work around but wanted to add this as part of this conversation.