Errors running libman CLI commands as a pre-build step in projects building in parallel on an Azure hosted agent

Start by reproducing the two-project parallel build using the libman clean && libman restore pre-build commands and the Azure Pipelines installation steps. Inspect how concurrent CLI invocations access .librarymanager/libman.config.json; done means both projects build successfully without the file-in-use exception.

Functional impact

Running into errors building projects in parallel on an Azure Pipelines hosted agent when they both invoke the libman CLI as a pre-build step.

Minimal repro steps

1. Create a Visual Studio solution with 2 projects that both invoke "libman clean && libman restore" as a pre-build step
2. Create an Azure Pipeline that
   1. Uses a 'dotnet' task to install the libman CLI to Agent.ToolsDirectory
      dotnet tool install Microsoft.Web.LibraryManager.Cli --tool-path="$(Agent.ToolsDirectory)"
   2. Uses a 'Powershell' task that adds Agent.ToolsDirectory to the environment variables
      Write-Host "##vso[task.setvariable variable=PATH;]${env:PATH};$(Agent.ToolsDirectory)";
   3. Builds the solution in parallel
3. Run the build on an Azure hosted agent

Expected result

Libman CLI commands run successfully

Actual result

Sometimes I see the following error output for one of the projects which causes the build to fail:

Unhandled Exception: System.TypeInitializationException: The type initializer for 'Microsoft.Web.LibraryManager.Configuration.Settings' threw an exception. ---> System.IO.IOException: The process cannot access the file 'C:\Users\VssAdministrator\.librarymanager\libman.config.json' because it is being used by another process.

Further technical details

I assume the issue is because both commands are running simultaneously and one puts a lock on libman.config.json so the other can't access it. I have run the build on a VM agent and do not see this error, though I installed libman globally on that machine so the 'install Libman CLI' step isn't part of the pipeline that runs on it.