allow ConnStats being marsheled to json

conn_stats.go

@@ -5,6 +5,7 @@ import (
 	"io"
 	"reflect"
 	"sync/atomic"
+	"encoding/json"
 
 	pp "github.com/anacrolix/torrent/peer_protocol"
 )
@@ -65,6 +66,10 @@ func (me *Count) String() string {
 	return fmt.Sprintf("%v", me.Int64())
 }
 
+func (me *Count) MarshalJSON() ([]byte, error) {
+	return json.Marshal(me.n)
+}
+
 func (cs *ConnStats) wroteMsg(msg *pp.Message) {
 	// TODO: Track messages and not just chunks.
 	switch msg.Type {