Near-field source with zenith angle distribution?

[markbandstra]

I would like to simulate a near-field rectangular source where photons are started with zenith angles belonging to a distribution, like cos(zenith) for example. Currently I can create a near-field rectangular plane source with emission normal to the plane (MapProfileBeam) or where emission is isotropic (FlatMap). One can specify a zenith distribution only for the far-field source FarFieldFileZenithDependent. So the source type I want is not currently possible, correct?

For now I think I can make a workaround by forcing photons from another source to scatter in a volume of the right shape and attenuation, which is what I am interested in simulating anyway, but I would rather decouple this process and have a "clean" source instead. I might be able to put together a PR if you think it would be useful.

[zoglauer]

I have put it on my todo list, but I am busy at the moment.