- #7091
- add `IKeyRewriterValueProvider` to remove rewritten keys or value providers containing such keys
- similar to `IBindingSourceValueProvider` except `CompositeValueProvider` keeps non-implementers around
- remove `after.Order == before.Order` special cases
- a premature optimization that could lead to lost inner provider replacements
- rework `EnumerableValueProviderTest` to ease test override in `CompositeValueProviderTest`
- add `EmptyValueProvider` fields to reduce `CompositeValueProvider` allocations
nits:
- remove Linq use in `CompositeValueProvider`
- do not create an unnecessary dictionary in `CompositeValueProvider.Filter(...)` methods
- accept VS suggestions, mostly pattern matching
We want this change to avoid MVC eagerly reading the form. This is good
for general perf and also for scenarios where you want read the body
yourself (large file uploads).
We DO have scenarios where you want to configure the value providers
per-request or also to change the limits on the value providers (form) so
it's worth keeping these around on the context.