Securely zero memory while avoiding compiler optimizations:
cross-platform secure intrinsics for zeroing memory, using FFI
to invoke OS intrinsics on stable Rust (with support for Linux,
Windows, macOS/iOS, FreeBSD, OpenBSD, NetBSD, DragonflyBSD),
or the unstable 'volatile_set_memory()` intrinsic on nightly.
No insecure fallbacks, no dependencies, no std, no functionality
besides securely zeroing memory.