grpc_v2.go
func (g GRPCLoggerV2) Warningf(format string, args ...interface{}) {
	g.l.Warningf(format, args...)
}
func (g GRPCLoggerV2) Warningf(format string, args ...interface{}) {
	g.l.Warningf(format, args...)
}
// Warningf calls Logger.Warningf method with provided arguments.