performance issue for AsyncLogWriter with "std::array<std::vector<std::string>, 2> queues"

[bluestn]

In AsyncLogWriter class, struct data has "queues" data member, defined as std::array<std::vectorstd::string, 2>, to buffer the output log messages, it's just a FIFO queue.

vector type may cause memory reallocation while data puts into the queue continuously, I think it will be better to change it to list type, to solve this performance issue.

thanks.