Added Operators.onDiscard

Author: artem-v

services-discovery/src/main/java/io/scalecube/services/discovery/ScalecubeServiceDiscovery.java

@@ -35,6 +35,7 @@
 import reactor.core.Exceptions;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
+import reactor.core.publisher.Operators;
 import reactor.core.publisher.SignalType;
 import reactor.core.publisher.Sinks;
 import reactor.core.publisher.Sinks.EmitFailureHandler;
@@ -44,6 +45,10 @@ public final class ScalecubeServiceDiscovery implements ServiceDiscovery {
 
   private static final Logger LOGGER = LoggerFactory.getLogger(ServiceDiscovery.class);
 
+  static {
+    Operators.enableOnDiscard(null, obj -> LOGGER.warn("[onDiscard] obj = {}", obj));
+  }
+
   private final ServiceEndpoint serviceEndpoint;
 
   private ClusterConfig clusterConfig;