Upgrade to RSocket 1.1-M2 and Reactor 2020.0.0-RC1

Closes gh-25729
Closes gh-25728

Author: rstoyanchev

build.gradle

@@ -25,9 +25,9 @@ configure(allprojects) { project ->
 		imports {
 			mavenBom "com.fasterxml.jackson:jackson-bom:2.11.2"
 			mavenBom "io.netty:netty-bom:4.1.51.Final"
-			mavenBom "io.projectreactor:reactor-bom:2020.0.0-SNAPSHOT"
+			mavenBom "io.projectreactor:reactor-bom:2020.0.0-RC1"
 			mavenBom "io.r2dbc:r2dbc-bom:Arabba-SR6"
-			mavenBom "io.rsocket:rsocket-bom:1.1.0-SNAPSHOT"
+			mavenBom "io.rsocket:rsocket-bom:1.1.0-M2"
 			mavenBom "org.eclipse.jetty:jetty-bom:9.4.31.v20200723"
 			mavenBom "org.jetbrains.kotlin:kotlin-bom:1.4.0"
 			mavenBom "org.jetbrains.kotlinx:kotlinx-coroutines-bom:1.3.9"
@@ -285,7 +285,7 @@ configure(allprojects) { project ->
 		repositories {
 			mavenCentral()
 			maven { url "https://repo.spring.io/libs-spring-framework-build" }
-			maven { url "https://repo.spring.io/snapshot" } // Reactor and RSocket
+			maven { url "https://repo.spring.io/milestone" } // Reactor
 		}
 	}
 	configurations.all {

spring-messaging/src/test/java/org/springframework/messaging/rsocket/DefaultRSocketRequesterBuilderTests.java

@@ -29,6 +29,7 @@
 import io.netty.buffer.ByteBufAllocator;
 import io.rsocket.ConnectionSetupPayload;
 import io.rsocket.DuplexConnection;
+import io.rsocket.RSocketErrorException;
 import io.rsocket.core.DefaultConnectionSetupPayload;
 import io.rsocket.core.RSocketConnector;
 import io.rsocket.frame.decoder.PayloadDecoder;
@@ -242,14 +243,12 @@ public ByteBuf setupFrame() {
 		}
 
 		@Override
-		public Mono<Void> send(Publisher<ByteBuf> frames) {
-			return Mono.empty();
+		public void sendFrame(int i, ByteBuf byteBuf) {
+			this.setupFrame = this.setupFrame == null ? byteBuf : this.setupFrame;
 		}
 
 		@Override
-		public Mono<Void> sendOne(ByteBuf frame) {
-			this.setupFrame = frame;
-			return Mono.empty();
+		public void sendErrorAndClose(RSocketErrorException e) {
 		}
 
 		@Override