ctor snippet

Transaction::Transaction(Id xid, int user_id, int rec_id,
                         event_base* pEventBase,
                         const BitrateConnInfo& bitrate_info,
                         const bfs::path& root,
                         const bfs::path& transaction_root,
                         int ingest_write_blocksize,
                         int ingest_recvbuf_size,
                         RecordResponseSignal::slot_type response,
                         int hdsMinToPublish,
                         int hdsFragDur)
    : mXid(xid),
      mUserIdRecId(user_id, rec_id),
      ...