avoid dependency on reactor-tcp when using a stomp broker relay [SPR-11153]

[spring-projects-issues]

zyro opened SPR-11153 and commented

currently, StompBrokerRelayMessageHandler uses ReactorNettyTcpClient as its the only implementation available. however, this implies a dependency on reactor-tcp (and reactor-core), which was tried to avoid in other places.

---

Affects: 4.0 RC2

Reference URL: 29934d7#commitcomment-4772250

Referenced from: commits 0a12f28