slave start io_thread 
 slave start sql_thread
same for stop


sql/lex.h:
  slave start <options>
sql/sql_lex.cc:
  slave start <options>
sql/sql_lex.h:
  slave start <options>
sql/sql_repl.cc:
  slave start <options>
sql/sql_yacc.yy:
  slave start <options>