Merge pull request #1321 from brendandburns/flush

Add a flush method to the websocket output stream.

Author: k8s-ci-robot

util/src/main/java/io/kubernetes/client/util/WebSocketStreamHandler.java

@@ -216,6 +216,24 @@ public WebSocketOutputStream(int stream) {
       this.stream = (byte) stream;
     }
 
+    @Override
+    public void flush() throws IOException {
+      if (state == State.CLOSED) {
+        throw new IOException("Socket is closed!");
+      }
+      int i = 0;
+      while (WebSocketStreamHandler.this.socket.queueSize() > 0) {
+        try {
+          Thread.sleep(100);
+        } catch (InterruptedException ex) {
+        }
+        // Wait a maximum of 10 seconds.
+        if (i++ > 100) {
+          throw new IOException("Timed out waiting for web-socket to flush.");
+        }
+      }
+    }
+
     @Override
     public void write(int b) throws IOException {
       write(new byte[] {(byte) b});