avoid flush repeatedly when has finished flushing (#978)

* avoid flush repeatedly when has finished flushing (#839)

* avoid repeat flush when position finish

* Formatting

Co-authored-by: jerry.l <jerry.l@binance.com>
Co-authored-by: Thomas Heigl <thomas.heigl@gmail.com>

* Revert "avoid flush repeatedly when has finished flushing (#839)"

This reverts commit d693aa5.

* avoid flush repeatedly when has finished flushing

---------

Co-authored-by: jackjoesh <jackjoesh@sina.com>
Co-authored-by: jerry.l <jerry.l@binance.com>
Co-authored-by: Thomas Heigl <thomas.heigl@gmail.com>

src/com/esotericsoftware/kryo/io/OutputChunked.java

@@ -60,8 +60,9 @@ public void flush () throws KryoException {
 			} catch (IOException ex) {
 				throw new KryoException(ex);
 			}
+		} else {
+			super.flush();
 		}
-		super.flush();
 	}
 
 	private void writeChunkSize () throws IOException {