[browser][debugger][MT] Make operations on dictionary thread-safe. (#87405)

* `ConcurrentDicionary` should be thread-safe.

Co-authored-by: Ankit Jain <radical@gmail.com>

---------

Co-authored-by: Ankit Jain <radical@gmail.com>

Author: ilonatommy

src/mono/wasm/debugger/DebuggerTestSuite/FirefoxInspectorClient.cs

@@ -143,7 +143,7 @@ public override async Task ProcessCommand(Result command, CancellationToken toke
                     return null;
 
                 var messageId = new FirefoxMessageId("", 0, from_str);
-                if (pending_cmds.Remove(messageId, out var item))
+                if (pending_cmds.TryRemove(messageId, out var item))
                     item.SetResult(Result.FromJsonFirefox(res));
                 else
                     logger.LogDebug($"HandleMessage: Could not find any pending cmd for {messageId}. msg: {msg}");
@@ -156,7 +156,7 @@ public override async Task ProcessCommand(Result command, CancellationToken toke
                 return null;
 
             var messageId = new FirefoxMessageId("", 0, from_str);
-            if (pending_cmds.Remove(messageId, out var item))
+            if (pending_cmds.TryRemove(messageId, out var item))
             {
                 item.SetResult(Result.FromJsonFirefox(res));
                 return null;
@@ -234,8 +234,7 @@ public override Task<Result> SendCommand(SessionId sessionId, string method, JOb
             throw new Exception($"No 'to' field found in '{args}'");
 
         msgId = new FirefoxMessageId("", 0, to_str);
-        pending_cmds[msgId] = tcs;
-        logger.LogTrace($"SendCommand: to: {args}");
+        pending_cmds.AddOrUpdate(msgId, tcs,  (key, oldValue) => tcs);
 
         var msg = args.ToString(Formatting.None);
         var bytes = Encoding.UTF8.GetBytes(msg);

src/mono/wasm/debugger/DebuggerTestSuite/InspectorClient.cs

@@ -2,7 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System;
-using System.Collections.Generic;
+using System.Collections.Concurrent;
 using System.Net;
 using System.Net.Sockets;
 using System.Net.WebSockets;
@@ -17,7 +17,7 @@ namespace DebuggerTests
 {
     internal class InspectorClient : DevToolsClient
     {
-        protected Dictionary<MessageId, TaskCompletionSource<Result>> pending_cmds = new Dictionary<MessageId, TaskCompletionSource<Result>>();
+        protected readonly ConcurrentDictionary<MessageId, TaskCompletionSource<Result>> pending_cmds = new();
         protected Func<string, string, JObject, CancellationToken, Task> onEvent;
         protected int next_cmd_id;
 
@@ -39,7 +39,7 @@ protected virtual Task HandleMessage(string msg, CancellationToken token)
                 return onEvent(res["sessionId"]?.Value<string>(), res["method"].Value<string>(), res["params"] as JObject, token);
 
             var id = res.ToObject<MessageId>();
-            if (!pending_cmds.Remove(id, out var item))
+            if (!pending_cmds.TryRemove(id, out var item))
                 logger.LogError($"Unable to find command {id}");
 
             item.SetResult(Result.FromJson(res));
@@ -95,7 +95,9 @@ public virtual Task<Result> SendCommand(SessionId sessionId, string method, JObj
             if (sessionId != SessionId.Null)
                 o.Add("sessionId", sessionId.sessionId);
             var tcs = new TaskCompletionSource<Result>();
-            pending_cmds[new MessageId(sessionId.sessionId, id)] = tcs;
+
+            MessageId msgId = new MessageId(sessionId.sessionId, id);
+            pending_cmds.AddOrUpdate(msgId, tcs,  (key, oldValue) => tcs);
 
             var str = o.ToString();