Issue: SPR-17012

1. Use special category prefix "spring-web.reactivestreams" for logging
of reactive streams signals in spring-web, since those are quite
verbose would fill the logs at TRACE.

2. Add and use loggers in request and websocket session implementations
separate from reactive streams bridge for regular TRACE logging.

3. Improve log messages and add where missing (e.g. for Reactor)

Issue: SPR-16898

Hiding it (at AbstractServerHttpRequest) complicates matters since
requests are often mutated and decorated, plus it's also possible to
implement the interface directly (we've one, albeit corner case).

Issue: SPR-16966

Issue: SPR-16966

1. Eliminate WebSocketClientSupport base class whose main value was
to provide logging but those methods get in the way of inserting a
log prefix.

2. Remove checks and synchronization in lifecycle methods of Jetty
client since underlying Jetty client already has that.

Issue: SPR-17017

Provide functions like ok() in RouterFunctionDsl to avoid
ServerResponse static imports.

Issue: SPR-17009

Issue: SPR-17014

Added a predicate that tests for multiple HTTP methods.

This commit improves the RouterFunctions.Builder based on conversations
had during the weekly team meeting.

Issue: SPR-16953

Issue: SPR-16894

Issue: SPR-17010

Issue: SPR-16305

Issue: SPR-16966

Issue: SPR-16966

Issue: SPR-16966

Issue: SPR-16966

This involves a new ResourceTransactionDefinition variant that JpaTransactionManager indicates a transaction-local EntityManager on. HibernateJpaDialect uses this indicator for hard read-only behavior.

Issue: SPR-16956

Issue: SPR-15588

Issue: SPR-16204

Issue: SPR-16982

LocalSessionFactoryBean automatically registers its containing BeanFactory as a BeanContainer when Hibernate 5.3 or higher is on the classpath.

Issue: SPR-16305

SessionHolder extends EntityManagerHolder now, allowing for @PersistenceContext and co to interact with HibernateTransactionManager's thread-bound transactions, and SpringSessionContext is capable of interacting with JpaTransactionManager by detecting a plain EntityManagerHolder as well.

Issue: SPR-17002

Issue: SPR-16831

This commit introduces a test to verify that multiple declarations of
@BootstrapWith that register the same TestContextBootstrapper type
(i.e., duplicates) do not result in an error.

Issue: SPR-17006

Issue: SPR-16956

Issue: SPR-16585
Issue: SPR-15903

Issue: SPR-16873