WebSocket client misses messages sent right after connection

[kittybwained]

It seems that AWS's WebSocket client API misses messages that get sent immediately after connection roughly 8 out of 10 times.

I've tested this by opening a connection to wss://echo.websocket.org and waiting for a message, which sometimes comes and sometimes doesn't. Testing with an online WebSocket tester tool gets the message every time.

The code for the main program above is as follows:

with Ada.Text_IO; use Ada.Text_IO;
with AWS;
with AWS.Net.WebSocket;
with AWS.Net.SSL;
procedure Main is
	type MySocket is new AWS.Net.WebSocket.Object with null record;
	overriding procedure On_Message(Self : in out MySocket; Str : String) is
	begin
		Ada.Text_IO.Put_Line ("++ Got message '" & Str & "'");
	end On_Message;

	Socket : MySocket;
begin
	AWS.Net.SSL.Initialize_Default_Config(Security_Mode => AWS.Net.SSL.TLS_Client, Client_Certificate => "", Check_Certificate => True);
	AWS.Net.WebSocket.Connect(Socket,"wss://echo.websocket.org");
	while Socket.Poll(Timeout => 2.0) loop
		null;
	end loop;
	Socket.Close("");
end Main;

For reference, here's what an online WebSocket test tool shows after connecting and disconnecting a few times:

Unfortunately, some APIs (e.g. Discord's Gateway API) rely on the server sending a message immediately after connecting, preventing these APIs from being used with AWS.

Also, in case it matters, I tested this from a freshly-built AWS from the master branch with SOCKET=openssl, on Debian Testing running under WSL2 (so kernel 5.15.167.4-microsoft-standard-WSL2).