4.x: Remove prefetch #7663

webclient/http2/src/main/java/io/helidon/webclient/http2/Http2ClientConnection.java

@@ -237,13 +237,15 @@ private void sendPreface(Http2ClientProtocolConfig config, boolean sendSettings)
             sendListener.frame(ctx, 0, http2Settings);
             writer.write(frameData);
         }
-        // First connection window update, with prefetch increment
-        Http2WindowUpdate windowUpdate = new Http2WindowUpdate(config.prefetch());
-        Http2Flag.NoFlags flags = Http2Flag.NoFlags.create();
-        Http2FrameData frameData = windowUpdate.toFrameData(null, 0, flags);
-        sendListener.frameHeader(ctx, 0, frameData.header());
-        sendListener.frame(ctx, 0, windowUpdate);
-        writer.write(frameData);
+        // Initial window size for connection is not configurable, subsequent update win update is needed
+        int connectionWinSizeUpd = config.initialWindowSize() - WindowSize.DEFAULT_WIN_SIZE;
+        if (connectionWinSizeUpd > 0) {
+            Http2WindowUpdate windowUpdate = new Http2WindowUpdate(connectionWinSizeUpd);
+            Http2FrameData frameData = windowUpdate.toFrameData(null, 0, Http2Flag.NoFlags.create());
+            sendListener.frameHeader(ctx, 0, frameData.header());
+            sendListener.frame(ctx, 0, windowUpdate);
+            writer.write(frameData);
+        }
     }
 
     private void start(Http2ClientProtocolConfig protocolConfig,

webclient/http2/src/main/java/io/helidon/webclient/http2/Http2ClientProtocolConfigBlueprint.java

@@ -84,15 +84,6 @@ default String type() {
     @ConfiguredOption("65535")
     int initialWindowSize();
 
-    /**
-     * First connection window update increment sent right after the connection is established.
-     * Defaults to {@code 33_554_432}.
-     *
-     * @return number of bytes the client is prepared to receive as data from all the streams combined
-     */
-    @ConfiguredOption("33554432")
-    int prefetch();
-
     /**
      * Timeout for blocking between windows size check iterations.
      *

webclient/tests/http2/src/test/java/io/helidon/webclient/tests/http2/ClientFlowControlTest.java

@@ -99,7 +99,6 @@ static void beforeAll() throws ExecutionException, InterruptedException, Timeout
 
         client = Http2Client.builder()
                 .baseUri("http://localhost:" + server.actualPort() + "/")
-                .protocolConfig(it -> it.prefetch(10000))
                 .build();
     }