Silent Failure if putty does not accept host key

I am using MiEngine for remote debugging in VS2017. I am launching it using the following command:
DebugAdapterHost.Launch /LaunchJson:"C:\Dev\DockerDotnetDebug\DebugSample\MIEngineConfig\MIEngineAttach.json

Using the following Config file:

{
  "version": "0.2.0",
  "adapter": "plink.exe",
  "adapterArgs": "-l root -pw **** localhost -P 2222 -batch -T ~/vsdbg/vsdbg --interpreter=vscode",
  "languageMappings": {
    "C#": {
      "languageId": "3F5162F8-07C6-11D3-9053-00C04FA302A1",
      "extensions": [ "*" ]
    }
  },
  "exceptionCategoryMappings": {
    "CLR": "449EC4CC-30D2-4032-9256-EE18EB41B62B",
    "MDA": "6ECE07A9-0EDE-45C4-8296-818D8FC401D4"
  },
  "configurations": [
    {
      "name": ".NET Core Attach",
      "type": "coreclr",
      "request": "attach",
   "processName": "dotnet"
    }
  ]
}

I find that unless I have previously connected to this machine using putty and accepted the hostkey, the command will fail silently. It will give no error, and have no visible effect for the user. It was very difficult to try and identify what is actually wrong, if anything.
Is it possible to add at least some kind of output?

Start at the DebugAdapterHost.Launch entry point and the plink.exe adapter invocation described in the issue. Reproduce the launch without an accepted host key, then trace how its failure is handled; done means the user receives visible error output instead of a silent failure.