Tagged enum usability & performance improvements

[cleaton]

1. Support multiple units with same field names
2. Move atom / tuple decode outside the type check if, to remove duplicate decode calls

Enum with 22 cases:
before:
tagged_enum_decode 1.56 M 642.48 ns ±1292.75% 634 ns 675 ns
after:
tagged_enum_decode 3.17 M 314.98 ns ±2092.02% 311 ns 343 ns

(~300ns is also the tagged_enum_encode latency on my machine)

[evnu]

Thanks for the PR @cleaton! I will need some time to review this as I am on vacation :)

[cleaton]

Thanks for the PR @cleaton! I will need some time to review this as I am on vacation :)

no problem, enjoy :)

[evnu]

Looks good to me, thanks!