modelFor is used constantly, the extra normalization and string splitting was causing measurable slowdown.
Merge pull request #2204 from stefanpenner/speed-up-model-for

modelFor is used constantly, the extra normalization and string splittin...
small perf, this map was unfortunately adding 5ms -> 8ms overhead for pushMany of N=1000. Removing it removed the overhead entirely.

Maybe at some point runtimes will actually optimize this…
Merge pull request #2207 from stefanpenner/small-perf

small perf, this map was unfortunately adding 5ms -> 8ms overhead for pu...
Refactor relationship handling code

Fixes #1919 #1814 #2057 #2191 #2177 #2125 #2100 #1848 #1790 #1532 #1389 #1308