reduce buffer size

transport/internet/kcp/config.go

@@ -49,8 +49,8 @@ func DefaultConfig() Config {
 		UplinkCapacity:   5,
 		DownlinkCapacity: 20,
 		Congestion:       false,
-		WriteBuffer:      8 * 1024 * 1024,
-		ReadBuffer:       8 * 1024 * 1024,
+		WriteBuffer:      4 * 1024 * 1024,
+		ReadBuffer:       4 * 1024 * 1024,
 	}
 }