Footnotes

• Contributors FSX read the manuscript of Candilio et al.; analysed their methods and data; suggested comment points and drafted this manuscript; responsible for this manuscript; and approved the final manuscript. RPL read the paper of Candilio et al.; analysed their data; revised the comment points and this manuscript; and approved the final manuscript. XLC read the manuscript of Candilio et al.; analysed their methods and data; revised the comment points and this manuscript; and approved the final manuscript.

• Competing interests None.

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