GH-1294 Remove TARGET_PROTOCOL from FunctionMessageUtils

Author: olegz

spring-cloud-function-context/src/main/java/org/springframework/cloud/function/utils/FunctionMessageUtils.java

@@ -40,10 +40,6 @@ public static String getSourceType(String functionDefinition, Message<?> message
 		return determineSourceFromHeaders(message.getHeaders());
 	}
 
-	public static String getTargetType(String functionDefinition, Message<?> message) {
-		return message.getHeaders().containsKey(MessageUtils.TARGET_PROTOCOL) ? (String) message.getHeaders().get(MessageUtils.TARGET_PROTOCOL) : "unknown";
-	}
-
 	private static String determineSourceFromHeaders(MessageHeaders headers) {
 		for (String key : headers.keySet()) {
 			if (key.equals(MessageUtils.SOURCE_TYPE)) {