module FFI
  interface _DataConverter[N, R, in C]
    def from_native: (N value, C ctx) -> R
    def native_type: (?ffi_auto_type? type) -> Type
    def to_native: (R value, C ctx) -> N
  end
  module DataConverter[N, R, in C]
    include _DataConverter[N, R, C]
  end
end