If WriteHeader is not called explicitly, the first call to Write

will trigger an implicit WriteHeader(http.StatusOK).
WriteHeader: Only one header may be written. Go does not currently!

weed/server/filer_server_handlers_read.go

@@ -150,10 +150,7 @@ func (fs *FilerServer) GetOrHeadHandler(w http.ResponseWriter, r *http.Request,
 		}
 	}
 
-	processRangeRequest(r, w, totalSize, mimeType, func(writer io.Writer, offset int64, size int64, httpStatusCode int) error {
-		if httpStatusCode != 0 {
-			w.WriteHeader(httpStatusCode)
-		}
+	processRangeRequest(r, w, totalSize, mimeType, func(writer io.Writer, offset int64, size int64) error {
 		if offset+size <= int64(len(entry.Content)) {
 			_, err := writer.Write(entry.Content[offset : offset+size])
 			if err != nil {