Great timing that Microsoft just released a drop-in replacement that's in order of magnitude faster: https://github.com/microsoft/garnet
Written in C# too, so it's incredibly easy to extend and write performant functions for.
It needs to be a bit more deployable though but they only just opened the repo, so I'll wait.
To be fair Microsoft has been working on Garnet for something like 4+ years and have already adopted it internally to reduce infrastructure costs.
Which has been their MO for the last few years. Improve .Net baseline performance, build high performance tools on top of it, dog food them, and then release them under open source licenses.