Lower CPU usage from RCheevos http stuff

src/BizHawk.Client.EmuHawk/RetroAchievements/RCheevos.GameInfo.cs

@@ -271,7 +271,7 @@ namespace BizHawk.Client.EmuHawk
 		private int SendHash(string hash)
 		{
 			var resolveHashRequest = new ResolveHashRequest(hash);
-			_inactiveHttpRequests.Push(resolveHashRequest);
+			PushRequest(resolveHashRequest);
 			resolveHashRequest.Wait(); // currently, this is done synchronously
 			return resolveHashRequest.GameID;
 		}
@@ -297,13 +297,12 @@ namespace BizHawk.Client.EmuHawk
 		private void InitGameData()
 		{
 			_activeModeUnlocksRequest = _gameData.InitUnlocks(Username, ApiToken, HardcoreMode);
-			_inactiveHttpRequests.Push(_activeModeUnlocksRequest);
+			PushRequest(_activeModeUnlocksRequest);
 
 			_inactiveModeUnlocksRequest = _gameData.InitUnlocks(Username, ApiToken, !HardcoreMode);
-			_inactiveHttpRequests.Push(_inactiveModeUnlocksRequest);
+			PushRequest(_inactiveModeUnlocksRequest);
 
-			var loadImageRequests = _gameData.LoadImages();
-			_inactiveHttpRequests.PushRange(loadImageRequests.ToArray());
+			PushRequests(_gameData.LoadImages());
 
 			foreach (var lboard in _gameData.LBoardEnumerable)
 			{
@@ -319,7 +318,7 @@ namespace BizHawk.Client.EmuHawk
 		private GameData GetGameData(int id)
 		{
 			var gameDataRequest = new GameDataRequest(Username, ApiToken, id, () => AllowUnofficialCheevos);
-			_inactiveHttpRequests.Push(gameDataRequest);
+			PushRequest(gameDataRequest);
 			gameDataRequest.Wait();
 			return gameDataRequest.GameData;
 		}

src/BizHawk.Client.EmuHawk/RetroAchievements/RCheevos.Http.cs

@@ -30,6 +30,7 @@ namespace BizHawk.Client.EmuHawk
 
 		private volatile bool _isActive;
 		private readonly Thread _httpThread;
+		private readonly AutoResetEvent _threadThrottle = new(false);
 
 		/// <summary>
 		/// Base class for all HTTP requests to rcheevos servers
@@ -154,6 +155,29 @@ namespace BizHawk.Client.EmuHawk
 			}
 		}
 
+		private void PushRequest(RCheevoHttpRequest request)
+		{
+			_inactiveHttpRequests.Push(request);
+			_threadThrottle.Set();
+		}
+
+		private void PushRequests(IEnumerable<RCheevoHttpRequest> requests)
+		{
+			if (requests is RCheevoHttpRequest[] requestsArray)
+			{
+				_inactiveHttpRequests.PushRange(requestsArray);
+			}
+			else
+			{
+				foreach (var request in requests)
+				{
+					_inactiveHttpRequests.Push(request);
+				}
+			}
+
+			_threadThrottle.Set();
+		}
+
 		private void HttpRequestThreadProc()
 		{
 			while (_isActive)
@@ -180,14 +204,26 @@ namespace BizHawk.Client.EmuHawk
 
 					return shouldRemove;
 				});
+
+				_threadThrottle.WaitOne(100000); // the default HTTP client timeout is 10 seconds
 			}
 
 			// typically I'd rather do this Dispose()
 			// but the Wait() semantics mean we can't do that on the UI thread
+			// so this thread is responsible for disposing
+
+			// add any remaining requests, we don't want a user to miss out on an achievement due to closing the emulator too soon...
+			while (_inactiveHttpRequests.TryPop(out var request))
+			{
+				request.DoRequest();
+				_activeHttpRequests.Add(request);
+			}
+
 			foreach (var request in _activeHttpRequests)
 			{
 				if (request is ImageRequest) continue; // THIS IS BAD, I KNOW (but don't want the user to wait for useless ImageRequests to finish)
-				request.Dispose(); // implicitly waits for the request to finish or timeout
+				// (probably wouldn't be so many ImageRequests anyways if we cache them on disk)
+				request.Dispose(); // implicitly waits for the request to finish or timeout (hope it doesn't timeout)
 			}
 		}
 

src/BizHawk.Client.EmuHawk/RetroAchievements/RCheevos.Login.cs

@@ -46,7 +46,7 @@ namespace BizHawk.Client.EmuHawk
 		private bool DoLogin(string username, string apiToken = null, string password = null)
 		{
 			var loginRequest = new LoginRequest(username, apiToken, password);
-			_inactiveHttpRequests.Push(loginRequest);
+			PushRequest(loginRequest);
 			loginRequest.Wait();
 
 			Username = loginRequest.Username;

src/BizHawk.Client.EmuHawk/RetroAchievements/RCheevos.Ping.cs

@@ -36,7 +36,7 @@ namespace BizHawk.Client.EmuHawk
 
 		private void StartGameSession()
 		{
-			_inactiveHttpRequests.Push(new StartGameSessionRequest(Username, ApiToken, _gameData.GameID));
+			PushRequest(new StartGameSessionRequest(Username, ApiToken, _gameData.GameID));
 		}
 
 		private sealed class PingRequest : RCheevoHttpRequest
@@ -67,7 +67,7 @@ namespace BizHawk.Client.EmuHawk
 
 		private void SendPing()
 		{
-			_inactiveHttpRequests.Push(new PingRequest(Username, ApiToken, _gameData.GameID, CurrentRichPresence));
+			PushRequest(new PingRequest(Username, ApiToken, _gameData.GameID, CurrentRichPresence));
 		}
 
 		private readonly byte[] _richPresenceBuffer = new byte[1024];

src/BizHawk.Client.EmuHawk/RetroAchievements/RCheevos.cs

@@ -197,7 +197,7 @@ namespace BizHawk.Client.EmuHawk
 			: base(mainForm, inputManager, tools, getConfig, raDropDownItems, shutdownRACallback)
 		{
 			_isActive = true;
-			_httpThread = new(HttpRequestThreadProc) { IsBackground = true, Priority = ThreadPriority.BelowNormal };
+			_httpThread = new(HttpRequestThreadProc) { IsBackground = true, Priority = ThreadPriority.BelowNormal, Name = "RCheevos HTTP Thread" };
 			_httpThread.Start();
 
 			_runtime = _lib.rc_runtime_alloc();
@@ -223,13 +223,10 @@ namespace BizHawk.Client.EmuHawk
 
 		public override void Dispose()
 		{
-			while (!_inactiveHttpRequests.IsEmpty)
-			{
-				// wait until all pending http requests are enqueued
-			}
-
 			_isActive = false;
-			_httpThread.Join();
+			_threadThrottle.Set(); // wakeup the thread
+			_httpThread.Join(); // note: the http thread handles disposing requests
+			_threadThrottle.Dispose();
 
 			_lib.rc_runtime_destroy(_runtime);
 			_runtime = IntPtr.Zero;
@@ -460,7 +457,7 @@ namespace BizHawk.Client.EmuHawk
 
 							if (cheevo.IsOfficial)
 							{
-								_inactiveHttpRequests.Push(new CheevoUnlockRequest(Username, ApiToken, evt->id, HardcoreMode, _gameHash));
+								PushRequest(new CheevoUnlockRequest(Username, ApiToken, evt->id, HardcoreMode, _gameHash));
 							}
 						}
 
@@ -545,7 +542,7 @@ namespace BizHawk.Client.EmuHawk
 						var lboard = _gameData.GetLboardById(evt->id);
 						if (!lboard.Invalid)
 						{
-							_inactiveHttpRequests.Push(new LboardTriggerRequest(Username, ApiToken, evt->id, evt->value, _gameHash));
+							PushRequest(new LboardTriggerRequest(Username, ApiToken, evt->id, evt->value, _gameHash));
 
 							if (!lboard.Hidden)
 							{