A signature to access CloudEvents' internal list of ExtensionFormat

Signed-off-by: Fabio José <fabiojose@gmail.com>

api/src/main/java/io/cloudevents/fun/ExtensionFormatAccessor.java

@@ -0,0 +1,25 @@
+package io.cloudevents.fun;
+
+import java.util.Collection;
+
+import io.cloudevents.Attributes;
+import io.cloudevents.CloudEvent;
+import io.cloudevents.extensions.ExtensionFormat;
+
+/**
+ * 
+ * @author fabiojose
+ *
+ */
+@FunctionalInterface
+public interface ExtensionFormatAccessor<A extends Attributes, T> {
+
+	/**
+	 * To get access to the internal collection of {@link ExtensionFormat} inside
+	 * the {@link CloudEvent} implementation
+	 * 
+	 * @param cloudEvent
+	 * @return
+	 */
+	Collection<ExtensionFormat> extensionsOf(CloudEvent<A, T> cloudEvent);
+}