Changing what was suggested by @radical.

Author: thaystg

src/mono/wasm/debugger/BrowserDebugProxy/MonoSDBHelper.cs

@@ -1224,9 +1224,7 @@ public async Task<MonoBinaryReader> GetTypePropertiesReader(SessionId sessionId,
             commandParamsWriter.Write(typeId);
 
             var reader = await SendDebuggerAgentCommand<CmdType>(sessionId, CmdType.GetProperties, commandParams, token);
-            var ms = new MemoryStream();
-            reader.BaseStream.CopyTo(ms);
-            typeInfo.PropertiesBuffer = ms.ToArray();
+            typeInfo.PropertiesBuffer = reader.ReadBytes((int)reader.BaseStream.Length);
             reader.BaseStream.Position = 0;
             return reader;
         }

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

@@ -8,6 +8,7 @@
 using Newtonsoft.Json.Linq;
 using System.Threading;
 using Xunit;
+using System.Collections.Generic;
 
 namespace DebuggerTests
 {
@@ -88,7 +89,7 @@ async Task<bool> CheckProperties(JObject pause_location)
 
             pause_location = await StepAndCheck(StepKind.Over, "dotnet://debugger-test.dll/debugger-custom-view-test.cs", bp.Value["locations"][0]["lineNumber"].Value<int>()+2, bp.Value["locations"][0]["columnNumber"].Value<int>(),  "run");
 
-            System.Collections.Generic.List<Task<bool>> tasks = new System.Collections.Generic.List<Task<bool>>();
+            List<Task<bool>> tasks = new();
             for (int i = 0 ; i < 10; i++)
             {
                 var task = CheckProperties(pause_location);