Footnotes

• Contributors AR drafted the original outline and version. All authors contributed to the multiple revisions and the overall concept, drafted part of the first version of the manuscript, reviewed and contributed to multiple other versions of the manuscript, approved the final version for submission and are accountable to all aspects of this work.

• Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

• Competing interests None declared.

• Provenance and peer review Not commissioned; externally peer reviewed.