How is the tsclient share created (in terms of Windows API)?

Question

Using the Windows RDP Client (mstsc.exe), I can share local resources with the host I'm connecting to.

For example if I share C:\, I can use it in the RDP session in \\tsclient\c.

What Windows API does the server side use to create the \\tsclient share?

(I'm not referring to the Virtual Channels within the RDP session, rather the Windows API calls for registering \\tsclient itself).

I'd like to create a virtual file system using the same approach, as an alternative to using a third party VFS driver such as Dokan or WinFsp.