Add comment about compiletime check.
Add comment about compiletime check.

Signed-off-by: Takeshi Yoneda <72d3043deb9ea484d21ffcca03f662fa81cbe321@tetrate.io>

andrewrk/zig,zig-lang/zig,andrewrk/zig,zig-lang/zig,zig-lang/zig