RESPite is an experimental library that provides high-performance low-level RESP (Redis, etc) parsing and serialization. It is used as the IO core for StackExchange.Redis v3+. You should not (yet) use it directly unless you have a very good reason to do so.
To suppress this message, add the following to your csproj file:
<NoWarn>$(NoWarn);SER004</NoWarn>
or more granularly / locally in C#:
#pragma warning disable SER004