--- wait(mutex)
    mutex Υåȥåɤߤޤ
    ConditionVariable#signal [ConditionVariable]ޤϡ
    ConditionVariable#broadcast [ConditionVariable]줿ʥ
    ȡmutexΥå¹Ծ֤Ȥʤޤ

    self ֤ޤ

