Closes gh-22837

Closes gh-22870

Closes gh-22874

Closes gh-22862

Includes dependency management plugin 1.0.7.

See gh-22821

Ensure that results returned from keySet, entrySet & values are tracked
to remove case insensitive keys from the source map.

Closes gh-22821

Closes gh-22842

Update `MergedAnnotation` with a `getRoot()` method that allows the
root direct annotation to be retrieved easily.

Closes gh-22818

See gh-22818

Closes gh-22804

Closes gh-22812

Following on 3ebbfa21 where the local
refCount was removed in favor of using the internal refCount of the
native data buffer, this commit ensures that LeakAwareDataBufferFactory
uses a PooledDataBufferFactory delegate by default.

There are also fixes for test issues with eager allocation uncovered by
these changes in StringDecoder and ResourceDecoder.

See gh-22503

Closes gh-22782

See gh-22782

See gh-22782

Following the 5.2 M1 release we can switch back to Reactor snapshots
and remove the workaround for a fix coming in Reactor Core 3.2.9.

The extra buffer release was used as a workaround for a reactor core
issue and should have already been removed as part of
b3bc2d92.

LeakAwareDataBuffer was keeping its own refCount rather than checking
through the delegate. This leads to false leak reports in a sequence
where an allocated buffer is retained and then sliced since it is not
aware of the changes to the refCount through the slice.

See gh-22738

Due to the changes in a7425c81, we no
longer need to execute tests using the JMXMP protocol in PERFORMANCE
builds.

This commit removes the JMXMP constant from the TestGroup enum and
updates affected tests, thereby effectively including such tests in
the standard build from now on.

See gh-22757

Closes gh-22766

Add a convenience method that allows a `MergedAnnotation` to be
converted into an `AnnotationAttributes` instance. Also rename
the `MapValues` enum to `Adapt` which generally seems to read
better.

Closes gh-22738

Add tests for `MissingMergedAnnotation`

See gh-21697

Delete `AnnotationAttributeExtractor` which is package private and
no longer used.

Closes gh-22753

Flow is a Kotlin Coroutines related cold asynchronous
stream of the data, that emits from zero to N (where N
can be unbounded) values and completes normally or with
an exception.

It is conceptually the Coroutines equivalent of Flux with
an extension oriented API design, easy custom operator
capabilities and some suspending methods.

This commit leverages Flow <-> Flux interoperability
to support Flow on controller handler method parameters
or return values, and also adds Flow based extensions to
WebFlux.fn. It allows to reach a point when we can consider
Spring Framework officially supports Coroutines even if some
additional work remains to be done like adding
interoperability between Reactor and Coroutines contexts.

Flow is currently an experimental API that is expected to
become final before Spring Framework 5.2 GA.

Close gh-19975