> So I'm proposing a C++ friendly interface, accessible by C and others
> languages and future compatible with a C++ client API.

What exactly means "future compatible with C++ client API"?

As to the Value interface - I'm ok with it as long as it supports
getters/setters for UTF8 strings.

> Proposed C++ API offers legacy handles to be used with current official API.

There's one issue with such model - it requires TLS in plugin. I like
Vlad's idea of having special DPB/TPB parameters for a current
attachment/transaction more attractive. Do you have any objections to it?

Roman