* Add `RSocketInboundGateway`; refactoring
* Extract an `AbstractRSocketConnector` for common client and server connectors logic
* Introduce an `IntegrationRSocketAcceptor` and `IntegrationRSocket` for the
mapping and handling logic of RSockets and messages in between
* Introduce an `IntegrationRSocketEndpoint` marker interface for Inbound Gateway mappings
* Add `RSocketInboundGateway` implementation, which is called from the
`IntegrationRSocketAcceptor` by the `IntegrationRSocketEndpoint` mapping
* Add `RSocketConnectedEvent` to emit when the client is connected to the server.
It does not make sense in Spring Integration to delegate such a logic into the
`RSocketInboundGateway`
* * Add `ServerRSocketConnector` to represent an RSocket server and
container for connected `RSocketRequester`s from clients
* Extract `accept(ConnectionSetupPayload setupPayload, RSocket sendingRSocket)`
server logic into an internal `ServerRSocketAcceptor` extension for the
`IntegrationRSocketAcceptor`
* Address PR comments:
- `RSocketConnectedEvent.toString()`
- `ApplicationEventPublisherAware` into the `ServerRSocketConnector`
- Log RSocket connection if no `this.applicationEventPublisher`
* Remove `handleConnectionSetupPayload()` from the `IntegrationRSocket`
since it is not delegated to the target handler
* Provide reasonable default `RSocketStrategies` for the
`AbstractRSocketConnector` and `RSocketInboundGateway`
* Add initial `RSocketInboundGatewayIntegrationTests`
* * Don't use `BytyBuffer` in the `RSocketConnectedEvent.toString()`
* Always `payload.retain()` when we convert `Payload` to `DataBuffer`
* Fix `IntegrationRSocketAcceptor.detectEndpoints()` stream logic
to really iterate over all the `IntegrationRSocketEndpoint` beans
* Fix test to use an explicit `ClientConfig` class for the
`@SpringJUnitConfig`: looks like JUnit 5 is OK to scan for `package
protected` classes as well
* Add request/reply tests into the `RSocketInboundGatewayIntegrationTests`
for both server and client sides
* * Remove `DataBuffer` from `RSocketConnectedEvent.toString()`
* * Fix Checkstyle violation in the RSocketInboundGatewayIntegrationTests
36e7041c26