Made the ForEachNode* functions in src/net.cpp more pragmatic and self documenting

[JeremyRubin]

No description provided.

[theuni]

Thanks! (On mobile, so bear with me) On the encapsulation PR, kaz suggested dropping the std::function arg in favor of a templated Callable in the header, to avoid incurring the stl overhead for simple lambdas. I think that's a good idea. Mind doing that at the same time here? So It'd look something like (all in the header) template <typename Callable> void ForEachNode(Callable&& func) { LOCK.. for(nodes...){ func(node); } } Also, if it would end up being simpler, you could implement them all terms of a basic (private, possibly static) version with no locking. With that, I believe it's also possible to eliminate ForEachNodeThen in favor of passing in a callable object, with its "then" function simply defined as its destructor. I'm not looking at the code now though, so i could be wrong on that.

[JeremyRubin]

Sure will code it up later today.

I don't think I'll do the destructor version as that seems fragile.

[theuni]

(I replied with this before, but seems it didn't go through. Disregard if this is a dupe)

Thanks! Looks good.

Nits:

• leading whitespace on some of the template lines
• are those tabs I see? 4 spaces please.

[JeremyRubin]

Should be all set.

[theuni]

Thanks, cherry-picked in.