Package slog defines an interface and default implementation for subsystem logging. Log level verbosity may be modified at runtime for each individual subsystem logger. The default implementation in this package must be created by the Backend type. Backends can write to any io.Writer, including multi-writers created by io.MultiWriter. Multi-writers allow log output to be written to many writers, including standard output and log files. Optional logging behavior can be specified by using the LOGFLAGS environment variable and overridden per-Backend by using the WithFlags call option. Multiple LOGFLAGS options can be specified, separated by commas. The following options are recognized: