The Scenario #

Here's the code in question:

WebSocket webSocket = new WebSocket("wss://ws-feed....");
webSocket.Connect();
webSocket.Send("message");
//执行一些操作
//仍在接收数据
Console.Write("What happens if I break indefinitely here?");

When the debugger hits an infinite breakpoint on the final line, what happens to any WebSocket messages sent by the server during that time?

Answer #

Great question—this all comes down to how WebSocketSharp handles message reception under the hood:

• Separate background thread for receiving
  WebSocketSharp doesn't rely on your main thread to listen for incoming messages. It spins up a dedicated background thread as soon as the connection is established. This thread runs independently, so even if your main thread is frozen at a breakpoint, the receiver thread keeps running and reading data from the WebSocket connection.

• Messages are buffered in an internal queue
  Any messages the server sends while your main thread is stuck are read by that background thread and stored in an internal message queue maintained by WebSocketSharp. These messages aren't discarded—they're just held in memory until your application can process them.

• Buffered messages are processed once the main thread resumes
  When you finally release the breakpoint and your main thread starts executing again, WebSocketSharp will start draining the message queue. It will trigger the OnMessage event (if you've subscribed to it) for each buffered message, in the exact order they were received from the server.

• Edge cases to consider

  • If the server floods your connection with an extremely large number of messages during the breakpoint, the queue could grow to consume a significant amount of system memory. But as long as your machine has enough RAM, no messages will be lost.
  • Some servers enforce idle timeout or heartbeat requirements. If your application's heartbeat logic runs on the main thread (which is stuck), the server might interpret the connection as inactive and close it. This is a server-side behavior, not a limitation of WebSocketSharp itself.

内容的提问来源于stack exchange，提问作者Maxim Gershkovich