Add vscode.workspace.fs.createWriteStream().

(see #84175)

For the Python extension, we currently use node’s fs.createWriteStream() for a variety of purposes:

1. downloading multi-MB files (and tracking progress)
   • calling into a third-party library that expects an fs.WriteStream
2. writing generated data out to a file a chunk at a time
3. writing log data out to a file, one entry at a time

For example:

• https://github.com/microsoft/vscode-python/blob/master/src/client/debugger/extension/adapter/logging.ts#L55
• https://github.com/microsoft/vscode-python/blob/master/src/client/common/net/fileDownloader.ts#L39

@jrieken

[connor4312]

[jrieken]

Let’s use this issue to track the open, close, read, write API. That quite low-level but the building block for stream.

https://github.com/microsoft/vscode/blob/ffe3749d5afb046f289d04f915d8d4ade47c028e/src/vs/vscode.proposed.d.ts#L152-L158