Imp: remove useless time format

[CoolIceV]

What this PR does:
Whether this log is output or not, the date will be formatted and cost a lot time, now it will be output without formatting as 2022-07-06 19:37:39.4692053 +0800 CST m=+0.775520901

Which issue(s) this PR fixes:
Fixes #1954

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[justxuewei]

Hi Yepeng, thanks for your contribution, I wonder how much the performance can be improved if the String() is removed? It seems that parsing the time takes a lots of time in the flame graph you posted on the issue #1954.

[CoolIceV]

I tested it roughly. When the QPS was high, there was about a ten or so milliseconds' improvement, but when the QPS was low, there didn't seem to be much optimization.

[binbin0325]

%s print time, eventually the String() function is called as well。 If must print the time, you can make a special note。
this should not matter in debug print log mode

[CoolIceV]

%s print time, eventually the String() function is called as well。 If must print the time, you can make a special note。 this should not matter in debug print log mode

I've now just delayed the String() call, meaning that if I don't want to print the log, I won't call the String() method, the original code would have called it whether or not the log was printed.
Original:

Modified:

[zhaoyunxing92]

如果只是打印当前时间的话是不是用log的时间就可以了

[CoolIceV]

如果只是打印当前时间的话是不是用log的时间就可以了

这个需要看log中的时间与所想要打印的时间会有多大的差距，这个本来就是debug用的，我觉得现在这样处理就可以，不用太纠结这个