[downloader] adjust default testnet downloader values, add sleep to unsuccessful download

cmd/harmony/default.go

@@ -139,25 +139,25 @@ var (
 	defaultTestNetSyncConfig = harmonyconfig.SyncConfig{
 		Enabled:        true,
 		Downloader:     false,
-		Concurrency:    4,
-		MinPeers:       4,
-		InitStreams:    4,
-		DiscSoftLowCap: 4,
-		DiscHardLowCap: 4,
+		Concurrency:    2,
+		MinPeers:       2,
+		InitStreams:    2,
+		DiscSoftLowCap: 2,
+		DiscHardLowCap: 2,
 		DiscHighCap:    1024,
-		DiscBatch:      8,
+		DiscBatch:      3,
 	}
 
 	defaultLocalNetSyncConfig = harmonyconfig.SyncConfig{
 		Enabled:        true,
 		Downloader:     true,
-		Concurrency:    4,
-		MinPeers:       4,
-		InitStreams:    4,
-		DiscSoftLowCap: 4,
-		DiscHardLowCap: 4,
+		Concurrency:    2,
+		MinPeers:       2,
+		InitStreams:    2,
+		DiscSoftLowCap: 2,
+		DiscHardLowCap: 2,
 		DiscHighCap:    1024,
-		DiscBatch:      8,
+		DiscBatch:      3,
 	}
 
 	defaultElseSyncConfig = harmonyconfig.SyncConfig{

hmy/downloader/downloader.go

@@ -203,6 +203,7 @@ func (d *Downloader) loop() {
 					time.Sleep(5 * time.Second)
 					trigger()
 				}()
+				time.Sleep(1 * time.Second)
 				continue
 			}
 			d.logger.Info().Int("block added", addedBN).

p2p/stream/common/streammanager/streammanager.go

@@ -125,6 +125,7 @@ func (sm *streamManager) loop() {
 
 		case <-sm.discCh:
 			if sm.coolDown.IsSet() {
+				sm.logger.Info().Msg("skipping discover for cool down")
 				continue
 			}
 			if discCancel != nil {