code: private void setHeartbeatInterval(long heartbeatInterval,
                                      long heartbeatRecheckInterval) {
      this.heartbeatInterval = heartbeatInterval;
      this.heartbeatRecheckInterval = heartbeatRecheckInterval;
      this.heartbeatExpireInterval = 2 * heartbeatRecheckInterval +
        10 * heartbeatInterval;
      ReplicationConfigKeys.blockInvalidateLimit =
        Math.max(ReplicationConfigKeys.blockInvalidateLimit,
                 20 * (int) (heartbeatInterval/1000L));
      
    }
docs: Set parameters derived from heartbeat interval.