Rare SHARING_VIOLATION when mounting UEFS VHD

[hach-que]

This probably just needs some retry logic around it.

Internal exception prior to running named build job: Failed to mount via UEFS: Grpc.Core.RpcException: Status(StatusCode="Internal", Detail="Failed to mount the package: System.InvalidOperationException: Failed to attach virtual disk: ERROR_SHARING_VIOLATION
    at Redpoint.Uefs.Package.Vhd.VhdPackageMounter.MountAsync(String packagePath, String mountPath, String writeStoragePath, WriteScratchPersistence persistenceMode)
    at Redpoint.Uefs.Daemon.Service.Mounting.PackageTagMounter.<>c__DisplayClass4_0.<<MountAsync>b__1>d.MoveNext()")
    at Redpoint.Uefs.Daemon.Service.Mounting.PackageTagMounter.<>c__DisplayClass4_0.<<MountAsync>b__1>d.MoveNext() --- End of stack trace from previous location ---
    at Redpoint.Uefs.Daemon.Transactional.Executors.AddMountTransactionExecutor.ExecuteTransactionAsync(ITransactionContext context, AddMountTransactionRequest transaction, CancellationToken cancellationToken)
    at Redpoint.Uefs.Daemon.Transactional.DefaultTransactionalDatabase.<>c__DisplayClass8_0`1.<<BeginTransactionAsync>b__0>d.MoveNext() --- End of stack trace from previous location ---
    at Redpoint.Uefs.Daemon.Transactional.DefaultTransactionalDatabase.<>c__DisplayClass8_0`1.<<BeginTransactionAsync>b__0>d.MoveNext() --- End of stack trace from previous location ---
    at Redpoint.Uefs.Daemon.Transactional.AbstractTransaction`2.ReleasableListener.DisposeAsync()
    at Redpoint.Uefs.Daemon.Service.Mounting.PackageTagMounter.MountAsync(IUefsDaemon daemon, MountContext context, MountPackageTagRequest request, TransactionListener onPollingResponse, CancellationToken cancellationToken)
    at Redpoint.Uefs.Daemon.Service.UefsGrpcService.<>c__DisplayClass12_0.<<MountPackageTag>b__0>d.MoveNext() --- End of stack trace from previous location ---
    at Redpoint.Uefs.Daemon.Service.UefsGrpcService.RunMountAsync(IServerStreamWriter`1 stream, MountContext mountContext, Func`2 operation) System.InvalidOperationException: Failed to mount via UEFS: Grpc.Core.RpcException: Status(StatusCode="Internal", Detail="Failed to mount the package: System.InvalidOperationException: Failed to attach virtual disk: ERROR_SHARING_VIOLATION
    at Redpoint.Uefs.Package.Vhd.VhdPackageMounter.MountAsync(String packagePath, String mountPath, String writeStoragePath, WriteScratchPersistence persistenceMode)
    at Redpoint.Uefs.Daemon.Service.Mounting.PackageTagMounter.<>c__DisplayClass4_0.<<MountAsync>b__1>d.MoveNext()")
    at Redpoint.Uefs.Daemon.Service.Mounting.PackageTagMounter.<>c__DisplayClass4_0.<<MountAsync>b__1>d.MoveNext() --- End of stack trace from previous location ---
    at Redpoint.Uefs.Daemon.Transactional.Executors.AddMountTransactionExecutor.ExecuteTransactionAsync(ITransactionContext context, AddMountTransactionRequest transaction, CancellationToken cancellationToken)
    at Redpoint.Uefs.Daemon.Transactional.DefaultTransactionalDatabase.<>c__DisplayClass8_0`1.<<BeginTransactionAsync>b__0>d.MoveNext() --- End of stack trace from previous location ---
    at Redpoint.Uefs.Daemon.Transactional.DefaultTransactionalDatabase.<>c__DisplayClass8_0`1.<<BeginTransactionAsync>b__0>d.MoveNext() --- End of stack trace from previous location ---
    at Redpoint.Uefs.Daemon.Transactional.AbstractTransaction`2.ReleasableListener.DisposeAsync()
    at Redpoint.Uefs.Daemon.Service.Mounting.PackageTagMounter.MountAsync(IUefsDaemon daemon, MountContext context, MountPackageTagRequest request, TransactionListener onPollingResponse, CancellationToken cancellationToken)
    at Redpoint.Uefs.Daemon.Service.UefsGrpcService.<>c__DisplayClass12_0.<<MountPackageTag>b__0>d.MoveNext() --- End of stack trace from previous location ---
    at Redpoint.Uefs.Daemon.Service.UefsGrpcService.RunMountAsync(IServerStreamWriter`1 stream, MountContext mountContext, Func`2 operation)
    at Redpoint.Uet.Workspace.ObservableMountOperation`1.RunAndWaitForMountIdAsync()
    at Redpoint.Uet.Workspace.ObservableMountOperation`1.RunAndWaitForMountIdAsync()
    at Redpoint.Uet.Workspace.ObservableMountOperation`1.RunAndWaitForMountIdAsync()
    at Redpoint.Uet.Workspace.VirtualWorkspaceProvider.MountAsync[TRequest](Func`5 , TRequest, CancellationToken)
    at Redpoint.Uet.Workspace.VirtualWorkspaceProvider.AllocateUefsPackageAsync(UefsPackageWorkspaceDescriptor, CancellationToken)
    at Redpoint.Uet.Workspace.VirtualWorkspaceProvider.AllocateUefsPackageAsync(UefsPackageWorkspaceDescriptor, CancellationToken)
    at Redpoint.Uet.Workspace.VirtualWorkspaceProvider.AllocateUefsPackageAsync(UefsPackageWorkspaceDescriptor, CancellationToken)
    at Redpoint.Uet.Workspace.VirtualWorkspaceProvider.GetWorkspaceAsync(IWorkspaceDescriptor, CancellationToken)
    at Redpoint.Uet.Workspace.PhysicalWorkspaceProvider.GetWorkspaceAsync(IWorkspaceDescriptor, CancellationToken)
    at Redpoint.Uet.BuildPipeline.Executors.Engine.DefaultEngineWorkspaceProvider.GetEngineWorkspace(BuildEngineSpecification, String, CancellationToken)
    at Redpoint.Uet.BuildPipeline.Executors.GitLab.GitLabBuildNodeExecutor.ExecuteBuildNodesAsync(BuildSpecification, BuildConfigDynamic`2[] , BuildConfigDynamic`2[] , IBuildExecutionEvents, IReadOnlyList`1, CancellationToken)