need to make a []byte of length len(b), not capacity len(b)

main.go

@@ -425,7 +425,7 @@ func (that *GlobalBackfeedManager) Handle(res http.ResponseWriter, req *http.Req
 		if len(b) == 0 {
 			continue
 		}
-		bcopy := make([]byte, 0, len(b))
+		bcopy := make([]byte, len(b))
 		copy(bcopy, b)
 		item := &BackfeedItem{
 			PrimaryShard:   GenShardHash(bcopy),