Temporary fix for s-c-stream GH-2178

This removes 'spring.cloud.stream.sendto.destination' headers from each incoming message

spring-cloud-function-context/src/main/java/org/springframework/cloud/function/context/catalog/SimpleFunctionRegistry.java

@@ -923,6 +923,7 @@ public class SimpleFunctionRegistry implements FunctionRegistry, FunctionInspect
 						: new OriginalMessageHolder(((Message) input).getPayload(), (Message<?>) input);
 			}
 			else if (input instanceof Message) {
+				input = this.filterOutHeaders((Message) input);
 				if (((Message) input).getPayload().getClass().getName().equals("org.springframework.kafka.support.KafkaNull")) {
 					return FunctionTypeUtils.isMessage(type) ? input : null;
 				}
@@ -958,6 +959,13 @@ public class SimpleFunctionRegistry implements FunctionRegistry, FunctionInspect
 			return convertedInput;
 		}
 
+		// TODO temporary fix for https://github.com/spring-cloud/spring-cloud-stream/issues/2178
+		// need a cleaner solution
+		@SuppressWarnings("unchecked")
+		private Message filterOutHeaders(Message message) {
+			return MessageBuilder.fromMessage(message).removeHeader("spring.cloud.stream.sendto.destination").build();
+		}
+
 		private boolean isExtractPayload(Message<?> message, Type type) {
 			if (FunctionTypeUtils.isCollectionOfMessage(type)) {
 				return true;