Add a delay to send the parallel requests.

content/browser/download/parallel_download_utils.h

Index: content/browser/download/parallel_download_utils.h
diff --git a/content/browser/download/parallel_download_utils.h b/content/browser/download/parallel_download_utils.h
index c788ac2ff02e0f6a85181f9da046d23a0d5ef721..0844e8d9c0e1e7d437629d4820aa43f0bc99dce5 100644
--- a/content/browser/download/parallel_download_utils.h
+++ b/content/browser/download/parallel_download_utils.h
@@ -35,6 +35,10 @@ CONTENT_EXPORT int64_t GetMinSliceSizeConfig();
 // Get the request count for parallel download from finch configuration.
 CONTENT_EXPORT int GetParallelRequestCountConfig();
 
+// Get the time delay to send parallel requests after the response of original
+// request is handled.
+CONTENT_EXPORT base::TimeDelta GetParallelRequestDelayConfig();
+
 }  //  namespace content
 
 #endif  // CONTENT_BROWSER_DOWNLOAD_PARALLEL_DOWNLOAD_UTILS_H_