// spdlog
// Fast C++ logging library.
spdlog is a fast C++ logging library. The whole point is that writing a line costs almost nothing, so nobody has to decide whether this code path deserves logging.
A logging call you can afford in a hot loop is the difference between having the record and guessing afterward.
Separate loggers per subsystem keep the stream readable when three components write at once.
Console today, rotating file tomorrow, both at once when an incident makes you want them.