[Data Streaming Service] Limit the backlog on data chunks under

saturation.

Author: JoshLind

config/src/config/state_sync_config.rs

@@ -153,7 +153,7 @@ impl Default for DataStreamingServiceConfig {
             global_summary_refresh_interval_ms: 50,
             max_concurrent_requests: 3,
             max_concurrent_state_requests: 6,
-            max_data_stream_channel_sizes: 500,
+            max_data_stream_channel_sizes: 300,
             max_request_retry: 3,
             max_notification_id_mappings: 300,
             progress_check_interval_ms: 100,