Add Struct#address_of(field) method?

[chuckremes]

I recently ran into an issue where I needed to pass the address of a Struct's field to a function (see inet_ntop(3)). I ended up having to base the base address of the struct into a Pointer and calculate the field's address using the offset. This isn't hard but it does seem like a reasonable enhancement to the Struct class.

Question: would a patch/PR implementing Struct#address_of(field) be accepted? It would essentially look like this (with specs):

  def address_of(field)
    Pointer.new(:uint8, self.pointer.address + offset_of(field.to_sym))
  end

Feedback?