add KcpMetric

improve creation of Bytebuf for flush
upgrade netty to 4.1.49.Final

Author: szhnet

README.md

@@ -9,7 +9,7 @@ To add a dependency using Maven:
 <dependency>
     <groupId>io.jpower.kcp</groupId>
     <artifactId>kcp-netty</artifactId>
-    <version>1.4.8</version>
+    <version>1.4.9</version>
 </dependency>
 ```
 

kcp-example/pom.xml

@@ -5,7 +5,7 @@
     <parent>
         <groupId>io.jpower.kcp</groupId>
         <artifactId>kcp-parent</artifactId>
-        <version>1.4.8</version>
+        <version>1.4.9</version>
     </parent>
     <modelVersion>4.0.0</modelVersion>
 

kcp-netty/pom.xml

@@ -5,7 +5,7 @@
     <parent>
         <groupId>io.jpower.kcp</groupId>
         <artifactId>kcp-parent</artifactId>
-        <version>1.4.8</version>
+        <version>1.4.9</version>
     </parent>
     <modelVersion>4.0.0</modelVersion>