ToFile creates a logger that will log any items at level or below to file, and defer any other output to glog (no matter what the level is).

None implements the Logger interface but does nothing with the log output.

StderrLog implements the Logger interface for stderr.

FileLogger logs the provided messages at level or below to the writer, or delegates to glog.

Logger is a simple interface that is roughly equivalent to glog.

VerboseLogger is roughly equivalent to glog's Verbose.