* [ACA-19] show hint on 400 error
* [ACA-19] unit test
* [ACA-19] small change
* [ACA-19] unit test
* [ACA-19] unit tests
* [ACA-19] avoid memory leaks with takeUntil
* [ACA-19] remove comment & formatting
* [ACA-19] update documentation
* [ACA-1889] Split Extending section into separate files
* [ACA-1889] Split Extending section into separate files
* [ACA-1889] Added recent changes and then deleted extending.md
* [ACA-1889] Added Tutorials section