code: func (b *backgroundFlusher) Process() {
  	b.logger.outputMutex.RLock()
  	defer b.logger.outputMutex.RUnlock()
  
  	for _, o := range b.logger.outputs {
  		o.OutputWrapper.Output.Flush()
  	}
  	if b.updateChan != nil {
  		close(b.updateChan)
  	}
  }
docs: // Called in order to flush all output's associated with the logger.