Provide a general use TaskExecutor for background tasks

[philwebb]

Several parts of Spring Boot, and even more Spring Cloud could benefit from running tasks in the background or in parallel (see #5066 for example). It would be useful if we provided a common TaskExecutor so that threads could be shared.

[vpavic]

👍

[snicoll]

I have such a need on start.spring.io as well: I'd like to process events asynchronously and it would be nice if I could easily configure an Executor for that. Note that it's slightly different than this description. We would have to bind (somehow) that to @EnableAsync

[cemo]

👍

[spencergibb]

Like @philwebb mentioned, spring-cloud has the need as well, see spring-cloud/spring-cloud-consul#146

[wilkinsona]

@sunlin901203 As @snicoll already asked, please use Stack Overflow for this sort of question