Setting up a Linux writecache as a RAM disk (2019)

For anyone wondering, this was written in 2019 and is no longer "new". I was confused by the following line since I recall this being available for sometime:

> By using the newly introduced dm-writecache device mapper Linux kernel module

Looked for a publication date, but nothing anywhere on the page other then timestamps in the command output mentioning 2019. Wayback machine confirms this as well[0]

[0] https://web.archive.org/web/20191124065801/https://www.admin...