code: func (sf StaticFile) AsStaticFIFO() (fifo StaticFIFO, ok bool) {
  	if sf.b.ss.Type == "fifo" {
  		return StaticFIFO{sf}, true
  	}
  
  	return
  }
docs: // AsStaticFIFO returns the StatifFile as a StaticFIFO if the
  // StaticFile represents a fifo. Otherwise, it returns the zero value
  // of StaticFIFO and false.