Macro simd_abstraction::simd_dispatch

macro_rules! simd_dispatch {
    (
        name        = $name:ident,
        signature   = $(for<$($lifetime:lifetime),+>)? fn($($arg_name: ident: $arg_type: ty),*) -> $ret:ty,
        fallback    = $fallback_fn:ident,
        simd        = $simd_fn:ident,
        safety      = {$($unsafe:ident)?},
    ) => { ... };
}