Specific -var-create in core dump debugging is incredible slow

Hello.

Summary
Debugging a C++ Core dump spent too much time waiting for the result of an specific -var-create (cutFrames).

The context is explained in this thread in C++ debugger extension.

• Details here - issue cpptools-12772

GDB command line does not suffer of this problem, overall debug took ~2 minutes.

Gathering debug info from MIENGINE

I was able to setup the debugger to debug OpenDebugAD7 process.

• Stepping through the code flow

https://github.com/microsoft/MIEngine/blob/074837ed159e41a3e550b41eb99cdc22d97ab519/src/MIDebugEngine/Engine.Impl/DebuggedProcess.cs#L2055

• Command: 1106-var-create - * "cutFrames"
• After executing the CmdAsyncInternal I lost what's going on:

https://github.com/microsoft/MIEngine/blob/074837ed159e41a3e550b41eb99cdc22d97ab519/src/MICore/Debugger.cs#L875-L887

• Status of waitingOperations:
  

• Step into MITransport > StreamTransport > Task.Wait(token) (execute the task?) and takes minutes to reach the next line -> return task.Result;
  https://github.com/microsoft/MIEngine/blob/074837ed159e41a3e550b41eb99cdc22d97ab519/src/MICore/Transports/StreamTransport.cs#L168

• After it returned, continuing stepping over I see this information on the overall status of the Debugger. There are two different exceptions, but I dont know if they're real or important at all for MICore.LocalTransport. _InvalidOperation*, process must exist before requested information can be determined.

• Nexts steps shows a ParseIssue? for it also shows the same for the other args (which seems to respond quickly)
  

Could you help me to identify what's going on? Any idea?
Thanks.

Start with the -var-create command flow in src/MIDebugEngine/Engine.Impl/DebuggedProcess.cs and follow CmdAsyncInternal in src/MICore/Debugger.cs. Inspect the wait in src/MICore/Transports/StreamTransport.cs while reproducing the core-dump case, then compare the slow request with the other arguments. Done means identifying the cause of the delay and documenting or fixing the affected behavior.