I'll copy over my [comment](https://github.com/libgit2/libgit2sharp/issues/647#issuecomment-41982258):

> Do we really want to `Obsolete` the current method or just have it delegate to the other overload with `credentials: null`?

I believe the compiler will warn that making `credentials` optional here would conflict with the existing method.

Though now that I think about it, we've historically not considered adding optional parameters to existing methods to be a breaking change, since the call pattern doesn't change (just need to recompile dependent apps). So maybe we don't need to keep the old method, just add the parameter to it?