Does `zbus::ProxyBuilder::build` really panic?

The docs for zbus::ProxyBuilder::build indicate that it panics if any details are missing. I see however that it returns Result.

Does it really panic under the hood if details as missing? I do see that it panics if the property cache is not initialized. Any hints on when that might happen?

(I'm mostly wanting to make sure I'm handling all possible error scenarios properly).