static public class ToSend {
        static enum mType {crequest, challenge, notification, ack}

        ToSend(mType type,
                long leader,
                long zxid,
                long electionEpoch,
                ServerState state,
                long sid,
                long peerEpoch) {

            this.leader = leader;
            this.zxid = zxid;
            this.electionEpoch = electionEpoch;
            this.state = state;
            this.sid = sid;
            this.peerEpoch = peerEpoch;
        }

        /*
         * Proposed leader in the case of notification
         */
        //被推举的leader的id
        long leader;

        /*
         * id contains the tag for acks, and zxid for notifications
         */
        // 被推举的leader的最大事务id
        long zxid;

        /*
         * Epoch
         */
        // 推举者的选举周期
        long electionEpoch;

        /*
         * Current state;
         */
        // 推举者的状态
        QuorumPeer.ServerState state;

        /*
         * Address of recipient
         */
        // 推举者的id
        long sid;
        
        /*
         * Leader epoch
         */
        // 被推举的leader的选举周期
        long peerEpoch;
    }
ToSend