Add identity-based accessors (and indices) to NetDir.

(Thank goodness for rust; we messed up the coherency in C here so
many times, but I'm pretty sure that this time around we can't have
gotten it wrong.)
3 jobs for main in 11 minutes and 13 seconds (queued for 4 seconds)
Status Name Job ID Coverage
  Build
passed rust-latest #36597
amd64

00:10:44

passed rust-latest-async-std #36598
amd64

00:01:01

passed rust-nightly #36599
amd64

00:11:13