GitLab

(It's a small diff -- just reflecting the fix for map returing absent.)

Previously, it was manually written prototypes of what gen "would" look like.

Now it's the real deal :3

Going to move it over to replace the (currently hand-written) gendemo
package shortly... but spread that over a few commits, in case the
diffs turn out interesting to look at.

Marshal is on par with basicnode.  Both basicnode and then gen stuff
does a solid job of alloc amortization on reads, so the dominant cost
remaining for both is in getting iterators.  Thus, they come out
pretty comparable overall.

Unmarshal is winning *nicely* over basicnode.  Roughly a third fewer
allocations, and gen is about 125% faster on the clock.

I haven't looked to see if unmarshal can be further improved with any
low-hanging-fruit sorts of fixes.  Wouldn't be surprised if it can.

We're gonna need more standard benchmarks... and in particular,
need them working without the marshal/unmarshal indirections.
Those are handy, but add a *lot* of noise from directions we're not
necessarily interested in when looking at different node impls.