copy invoker to new invocation in generic filter

Author: chickenlj

dubbo-rpc/dubbo-rpc-api/src/main/java/org/apache/dubbo/rpc/filter/GenericFilter.java

@@ -139,6 +139,7 @@ public Result invoke(Invoker<?> invoker, Invocation inv) throws RpcException {
                     }
                 }
                 RpcInvocation rpcInvocation = new RpcInvocation(method, args, inv.getAttachments(), inv.getAttributes());
+                rpcInvocation.setInvoker(inv.getInvoker());
                 rpcInvocation.setTargetServiceUniqueName(inv.getTargetServiceUniqueName());
 
                 return invoker.invoke(rpcInvocation);