// LevelFlag uses the standard library's flag.Var to declare a global flag // with the specified name, default, and usage guidance. The returned value is // a pointer to the value of the flag. // // If you don't want to use the flag package's global state, you can use any // non-nil *Level as a flag.Value with your own *flag.FlagSet. func LevelFlag(name string, defaultLevel zapcore.Level, usage string) *zapcore.Level { … }