memory.go
func (b *ChannelMemoryBackend) Log(level Level, calldepth int, rec *Record) error {
	b.incoming <- rec
	return nil
}
func (b *ChannelMemoryBackend) Log(level Level, calldepth int, rec *Record) error {
	b.incoming <- rec
	return nil
}
// Log implements the Log method required by Backend.