By Adam Nagy
When opening a drawing you have some options:
If you check the possible values of the Options argument of Documents.OpenWithOptions in the API Reference then you can find the one corresponding to"Skip all unresolved files" - it's named "SkipAllUnresolvedFiles"
You won't find the equivalent of "Fast Open (Skip All)" listed though. It seems it was left out accidentally, but only from the API Reference. It is implemented in the API and can be used. It's named "FastOpen"