At what point does the subscription take place? (spring webflux)
Solution 1:
It's the framework (spring-webflux) that subscribes to the returned Mono or Flux. For example if you use Netty (that's the default), then subscription happens here based on my debugging:
https://github.com/reactor/reactor-netty/blob/db27625064fc78f8374c1ef0af3160ec3ae979f4/reactor-netty-http/src/main/java/reactor/netty/http/server/HttpServer.java#L962
Also, this article might be of help to understand what happens when: https://spring.io/blog/2019/03/06/flight-of-the-flux-1-assembly-vs-subscription