Moved method onFlushed() to ISession.

Signed-off-by: Simone Bordet <simone.bordet@gmail.com>

jetty-http2/http2-common/src/main/java/org/eclipse/jetty/http2/HTTP2Connection.java

@@ -199,8 +199,7 @@ public class HTTP2Connection extends AbstractConnection implements WriteFlusher.
     @Override
     public void onFlushed(long bytes) throws IOException
     {
-        // TODO: add method to ISession ?
-        ((HTTP2Session)session).onFlushed(bytes);
+        session.onFlushed(bytes);
     }
 
     protected class HTTP2Producer implements ExecutionStrategy.Producer

jetty-http2/http2-common/src/main/java/org/eclipse/jetty/http2/HTTP2Session.java

@@ -975,7 +975,8 @@ public abstract class HTTP2Session extends ContainerLifeCycle implements ISessio
     {
     }
 
-    void onFlushed(long bytes) throws IOException
+    @Override
+    public void onFlushed(long bytes) throws IOException
     {
         flusher.onFlushed(bytes);
     }

jetty-http2/http2-common/src/main/java/org/eclipse/jetty/http2/ISession.java

@@ -18,6 +18,8 @@
 
 package org.eclipse.jetty.http2;
 
+import java.io.IOException;
+
 import org.eclipse.jetty.http2.api.Session;
 import org.eclipse.jetty.http2.api.Stream;
 import org.eclipse.jetty.http2.frames.DataFrame;
@@ -129,6 +131,14 @@ public interface ISession extends Session
      */
     public void onFrame(Frame frame);
 
+    /**
+     * <p>Callback method invoked when bytes are flushed to the network.</p>
+     *
+     * @param bytes the number of bytes flushed to the network
+     * @throws IOException if the flush should fail
+     */
+    public void onFlushed(long bytes) throws IOException;
+
     /**
      * @return the number of bytes written by this session
      */