how to serve a large file using RxJava2 with Micronaut

FileController

@Controller("/test")
class FileController{

    @Get(value = "/{file}", produces = MediaType.IMAGE_GIF)
    Flowable<byte[]> image(@PathVariable String file) {        
    
      Flowable.create({ emitter ->
          new File(file).withInputStream{ inputStream ->
                int size=1024
              byte[]buff = inputStream.readNBytes(size)
              while( buff.length == size){
                  emitter.onNext(buff)
                  buff = inputStream.readNBytes(size)
              }
              emitter.onNext(buff)
              emitter.onComplete()
          }
      }, BackpressureStrategy.BUFFER)
  }
}