I have tried splitting up this feature flag into three different ones:

bstr-deserialize = ["dep:bstr"]
bstr-serialize = ["dep:bstr"]
bstr-owned = ["bstr-serialize"]

• bstr-deserialize would cause the deserialize code to emit &BStr instead of &str.
• bstr-serialize would allow you to build a Offset<str> from a &BStr/BString.
• bstr-owned would cause the owned structs for tables/unions to use BString instead of String.

I ran into an issue with the error handling in the TryFrom code that converts Refs into owned structs in the case where only bstr-deserialize was enabled. The problem is that the TryFrom code needs to return a planus::Error and this is hard to do in some cases.

This PR is very stale. I am also no longer sure this is the right way to do it.