Paket 'hangs' without any output for several minutes

Description

Started a build in VS 2017 (net sdk integration):

1>Build started 2018-11-08 10:47:19.
1>Target PaketRestore:
1>  Paket version 5.181.1

// after some minutes

1>  Starting full restore process.
1>  Performance:
1>   - Disk IO: 191 milliseconds
1>   - Runtime: 3 minutes, 17 second

Repro steps

Not clear but there shouldn't be too many places in the code which can be responsible before Starting full restore process and after printing the version.

This seems to happen when VSCode + Visual Studio 2017 is open and I add a new package with paket install and "rightclick -> build" in Visual Studio (I guess VSCode or VS is doing some paket commands behind the scenes)

Expected behavior

I feel like paket is waiting for another process to exit and should tell me that. Even better would be to just work faster ;)

Actual behavior

Nothing

Known workarounds

Wait

Start by reproducing the reported sequence with VS Code and Visual Studio 2017: run paket install, then build after adding a package. Trace the restore path between the Paket version output and “Starting full restore process,” and inspect whether another process is blocking it. Done means identifying the cause and either removing the wait or reporting a clear diagnostic.