I am aware of the Shapiro time delay, though in my books I always had it down as the particular case of light traveling around some central mass like a star.
I guess what my question was more targeted at was how to calculate something like this in general (and not just for the Schwarzschild...
Suppose you have the following situation:
We have a spacetime that is asymptotically flat. At some position A which is in the region that is approximately flat, an observer sends out a photon (for simplicity, as I presume that any calculations involved here become easier if we consider a...