handle_io_slave:

last_add_time = now() 

  tokens = read_binlog_speed_limit //there are some initial tokens in the bucket

  while(true){

    event = read_event() 

      if (read_binlog_speed_limit > 0) {

        if (tokents > TOKEN_MAX) { 

          tokens = TOKEN_MAX 

            last_add_time = now() 

        } 

        do{ 

          //put some token

          tokens = tokens + (now()-last_add_time)*read_binlog_speed_limit;

          //if the token is not enough, sleep some time.

          if(tokens < event.real_network_read_len)

            sleep((event.len-tokens)/speed_limit) 

        } 

      }

    write_event(event) 

  }