Expose flush() method on Logback and Log4j appenders.

Author: stevejagodzinski

src/main/java/com/splunk/logging/HttpEventCollectorLog4jAppender.java

@@ -245,6 +245,10 @@ public void append(final LogEvent event)
         );
     }
 
+    public void flush() {
+        sender.flush();
+    }
+
     @Override
     public boolean stop(long timeout, TimeUnit timeUnit) {
         this.sender.close();

src/main/java/com/splunk/logging/HttpEventCollectorLogbackAppender.java

@@ -119,6 +119,12 @@ public void start() {
         super.start();
     }
 
+    public void flush() {
+        if (started) {
+            sender.flush();
+        }
+    }
+
     @Override
     public void stop() {
         if (!started)
@@ -400,5 +406,7 @@ private static long parseLong(String string, int defaultValue) {
             return defaultValue;
         }
     }
+
+
 }