Add retry delay

src/internal/constants.ts

@@ -11,6 +11,9 @@ export enum CompressionMethod {
   Zstd = 'zstd'
 }
 
+// The default delay in milliseconds between retry attempts.
+export const RetryDelay = 5000
+
 // Socket timeout in milliseconds during download.  If no traffic is received
 // over the socket during this period, the socket is destroyed and the download
 // is aborted.