* Implements require_transactional

* support wasm

* only enable for debug build

* remove wasm support and add feature flag

* Apply suggestions from code review

Co-authored-by: Bastian Köcher <[email protected]>

* only use check for debug_assertions

* update per review

* update docs

* Apply suggestions from code review

Co-authored-by: Bastian Köcher <[email protected]>

* remove duplicated tests

* fix test

Co-authored-by: Bastian Köcher <[email protected]>