use a new thread safe map

pkg/chunk/download.go

@@ -112,7 +112,6 @@ func (d *Downloader) downloadFromAPI(request *Request, buffer []byte, delay int6
 	downloadURL := resp.Download
 	req, err := http.NewRequest("GET", downloadURL, nil)
 	if nil != err {
-		d.log.Debugf("request init error: %v", err)
 		return fmt.Errorf("could not create request object %s %s from API", request.file.Path, request.file.Link)
 	}
 	req.Header.Add("Range", fmt.Sprintf("bytes=%v-%v", request.offsetStart, request.offsetEnd-1))

pkg/chunk/storage.go

@@ -381,23 +381,18 @@ func (s *Storage) Store(id RequestID, bytes []byte) (err error) {
 
 	if nil != chunk {
 		if chunk.valid(id) {
-			s.log.Debugf("Create chunk %v (exists: valid)", id)
 			return nil
 		}
 		s.log.Warnf("Create chunk %v(exists: overwrite)", id)
 	} else {
 		index := s.stack.Pop()
 		if index == -1 {
-			s.log.Debugf("Create chunk %v (failed)", id)
 			return fmt.Errorf("no buffers available")
 		}
 		chunk = s.buffers[index]
 		deleteID := chunk.id
 		if blankRequestID != deleteID {
 			delete(s.chunks, deleteID)
-			s.log.Debugf("Create chunk %v (reused)", id)
-		} else {
-			s.log.Debugf("Create chunk %v (stored)", id)
 		}
 		s.chunks[id] = index
 		chunk.item = s.stack.Push(index)