set/get
设定KEY 而不论是否存在
set abc 0 0 8
123456789
CLIENT_ERROR bad data chunk
ERROR
get abc
END
set abc 0 0 8
12345678
STORED
get abc
VALUE abc 0 8
12345678
END
set def 0 0 6
ab
STORED
get def
VALUE def 0 6
ab
END
delete
删除存在的KEY
get abc
VALUE abc 0 8
12345678
END
delete abc
DELETED
get abc
END
delete ioio
NOT_FOUND
