Reactor Netty resources created by the auto-configured WebClient may outlive the application context

[wilkinsona]

We should hopefully be able to use a ReactorResourceFactory bean and a custom ReactorClientHttpConnector to tie the lifecycle of the resources to the application context. See SPR-16963 for some background information.

[rstoyanchev]

I've updated the docs.

The WebFlux starter can still rely on global resources, I think. It's the idiomatic way with Reactor Netty and will work better alongside other libraries that embed Reactor Netty. Perhaps declare ReactorResourceFactory as a bean with globalResources=true just in case. Can the application context be closed and re-recreated in the same process? There is the devtools case based on #9146, and perhaps declaring the factory could be used to clean that up a bit.

For Spring MVC, similar reasoning. Clearly when running in a WAR with the SpringBootServletInitializer, the ReactorResourceFactory in global mode is needed, but that should also be sufficient.

[rstoyanchev]

A couple of data points. The CF Java client manages its own resources. The RabbitMQ HTTP management client doesn't do anything special for resources, and hence participates in global resources by default.

I've also created a related issue reactor/reactor-netty#416.