Opening single C# does not launch the server

When I fire up VS Code (without any workspace/folder) and open a C# file, it does not start the OmniSharp server and I don't get any useful autocompletion.

I'd expect it to provide basic autocompletion for the standard library, renames of local variables and similar goodness that does not require much knowledge of the context of that C# file.

It actually seems to work when I open a C# in an empty folder (without any project information), I'd this to work in a similar way. Although it also could probably try to figure in which context is the C# file used.

In case you would not like to implement this feature, warning user that OmniSharp is actually disabled and not broken would be very nice, this is quite confusing (my friend actually just could not figure out how to get this C# extension working)

Logs are empty - nothing is started

## Environment information ##

**VSCode version**: 1.39.2
**C# Extension**: 1.21.7

Mono Information
OmniSharp using built-in mono
Dotnet Information
.NET Core SDK (reflecting any global.json):
Version: 3.1.100-preview1-014459
Commit: ac3b59712d

Runtime Environment:
OS Name: arch
OS Version: 5.3.10-arch1-1
OS Platform: Linux
RID: linux-x64
Base Path: /opt/dotnet/sdk/3.1.100-preview1-014459/

Host (useful for support):
Version: 3.1.0-preview1.19506.1
Commit: bbf5542781

.NET Core SDKs installed:
2.2.108 [/opt/dotnet/sdk]
3.1.100-preview1-014459 [/opt/dotnet/sdk]

.NET Core runtimes installed:
Microsoft.AspNetCore.All 2.2.6 [/opt/dotnet/shared/Microsoft.AspNetCore.All]
Microsoft.AspNetCore.App 2.2.6 [/opt/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.0-preview1.19508.20 [/opt/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.NETCore.App 2.2.6 [/opt/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.0-preview1.19506.1 [/opt/dotnet/shared/Microsoft.NETCore.App]

To install additional .NET Core runtimes or SDKs:
https://aka.ms/dotnet-download

Visual Studio Code Extensions

|Extension|Author|Version|
|---|---|---|
|auto-align|bladnman|0.0.13|
|clang-format|xaver|1.9.0|
|clipboard-history|Anjali|1.0.7|
|code-lol|EnsignPayton|1.0.1|
|code-spell-checker|streetsidesoftware|1.7.20|
|csharp|ms-vscode|1.21.7|
|csharpextensions|jchannon|1.3.1|
|fish-vscode|skyapps|0.2.1|
|ghosttext|tokoph|1.1.0|
|gitblame|waderyan|3.0.1|
|Ionide-fsharp|Ionide|4.3.1|
|language-haskell|justusadam|2.6.0|
|Nix|bbenoist|1.0.1|
|python|ms-python|2019.10.44104|
|rust|rust-lang|0.7.0|
|snippetica-csharp|josefpihrt-vscode|0.9.1|
|theme-base16grayscale|brettlempereur|1.1.0|
|trailing-spaces|shardulm94|0.3.1|
|vim|vscodevim|1.11.3|
|vscode-clang|mitaki28|0.2.3|
|vscode-hie-server|alanz|0.0.30|
|vscodeintellicode|VisualStudioExptTeam|1.2.0|
|vsliveshare|ms-vsliveshare|1.0.1245|;

Also note that my friend observes the same behavior with a very different set of extensions.