How to open several tabs in bulk or without activating every opened tab - OpenDocumentOptions(bool:activate) doesn't seem to work

[luislhg]

Hello, I'm developing an extension that should keep track of tabs (save, open and restore) based on the current branch or feature the user is working with.

The code below does open every tab as expected, but it is tremendously slow.

1. Because it opens each one in sequence
   (I'd expect some way to specify and open multiple files at once, just like when you open a .sln or .csproj, VS will open all tabs really quickly)

2. The activate: false doesn't seem to take effect, each tab is activated/rendered before opening the next one.

// TODO: Find some way to open documents faster, without activating/viewing one by one.
// Open documents.
var documents = Extensibility.Documents();
var openDocumentOptions = new OpenDocumentOptions(activate: false);
foreach (var document in savedDocuments)
{
    await documents.OpenDocumentAsync(new Uri(document.FilePath), openDocumentOptions, cancellationToken);
}